diff --git a/qa/rpc-tests/dip3-deterministicmns.py b/qa/rpc-tests/dip3-deterministicmns.py
index eebbcaf10f..02eb80acfe 100755
--- a/qa/rpc-tests/dip3-deterministicmns.py
+++ b/qa/rpc-tests/dip3-deterministicmns.py
@@ -655,7 +655,7 @@ class DIP3Test(BitcoinTestFramework):
         address = node.getnewaddress()
         key = node.getnewaddress()
         blsKey = node.bls('generate')
-        assert_raises_jsonrpc(None, "bad-tx-type", node.protx, 'register_fund', address, '127.0.0.1:10000', key, blsKey['public'], key, 0, address)
+        assert_raises_jsonrpc(None, "bad-tx-type-dip3", node.protx, 'register_fund', address, '127.0.0.1:10000', key, blsKey['public'], key, 0, address)
 
     def test_success_create_protx(self, node):
         address = node.getnewaddress()
diff --git a/src/evo/cbtx.cpp b/src/evo/cbtx.cpp
index 9d0d5cd904..b7a8577606 100644
--- a/src/evo/cbtx.cpp
+++ b/src/evo/cbtx.cpp
@@ -12,7 +12,9 @@
 
 bool CheckCbTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CValidationState& state)
 {
-    AssertLockHeld(cs_main);
+    if (tx.nType != TRANSACTION_COINBASE) {
+        return state.DoS(100, false, REJECT_INVALID, "bad-cbtx-type");
+    }
 
     if (!tx.IsCoinBase()) {
         return state.DoS(100, false, REJECT_INVALID, "bad-cbtx-invalid");
@@ -20,7 +22,7 @@ bool CheckCbTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CValidatio
 
     CCbTx cbTx;
     if (!GetTxPayload(tx, cbTx)) {
-        return state.DoS(100, false, REJECT_INVALID, "bad-tx-payload");
+        return state.DoS(100, false, REJECT_INVALID, "bad-cbtx-payload");
     }
 
     if (cbTx.nVersion > CCbTx::CURRENT_VERSION) {
@@ -37,15 +39,13 @@ bool CheckCbTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CValidatio
 // This can only be done after the block has been fully processed, as otherwise we won't have the finished MN list
 bool CheckCbTxMerkleRootMNList(const CBlock& block, const CBlockIndex* pindex, CValidationState& state)
 {
-    AssertLockHeld(cs_main);
-
     if (block.vtx[0]->nType != TRANSACTION_COINBASE) {
         return true;
     }
 
     CCbTx cbTx;
     if (!GetTxPayload(*block.vtx[0], cbTx)) {
-        return state.DoS(100, false, REJECT_INVALID, "bad-tx-payload");
+        return state.DoS(100, false, REJECT_INVALID, "bad-cbtx-payload");
     }
 
     if (pindex) {
@@ -63,7 +63,6 @@ bool CheckCbTxMerkleRootMNList(const CBlock& block, const CBlockIndex* pindex, C
 
 bool CalcCbTxMerkleRootMNList(const CBlock& block, const CBlockIndex* pindexPrev, uint256& merkleRootRet, CValidationState& state)
 {
-    AssertLockHeld(cs_main);
     LOCK(deterministicMNManager->cs);
 
     CDeterministicMNList tmpMNList;
diff --git a/src/evo/deterministicmns.cpp b/src/evo/deterministicmns.cpp
index 97bbb8df4a..724b33cd33 100644
--- a/src/evo/deterministicmns.cpp
+++ b/src/evo/deterministicmns.cpp
@@ -676,7 +676,7 @@ int64_t CDeterministicMNManager::GetSpork15Value()
 
 bool CDeterministicMNManager::IsProTxWithCollateral(const CTransactionRef& tx, uint32_t n)
 {
-    if (tx->nVersion < 3 || tx->nType != TRANSACTION_PROVIDER_REGISTER) {
+    if (tx->nVersion != 3 || tx->nType != TRANSACTION_PROVIDER_REGISTER) {
         return false;
     }
     CProRegTx proTx;
diff --git a/src/evo/providertx.cpp b/src/evo/providertx.cpp
index ab9022f116..36e6b9a5bb 100644
--- a/src/evo/providertx.cpp
+++ b/src/evo/providertx.cpp
@@ -76,11 +76,13 @@ static bool CheckInputsHash(const CTransaction& tx, const ProTx& proTx, CValidat
 
 bool CheckProRegTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CValidationState& state)
 {
-    AssertLockHeld(cs_main);
+    if (tx.nType != TRANSACTION_PROVIDER_REGISTER) {
+        return state.DoS(100, false, REJECT_INVALID, "bad-protx-type");
+    }
 
     CProRegTx ptx;
     if (!GetTxPayload(tx, ptx)) {
-        return state.DoS(100, false, REJECT_INVALID, "bad-tx-payload");
+        return state.DoS(100, false, REJECT_INVALID, "bad-protx-payload");
     }
 
     if (ptx.nVersion > CProRegTx::CURRENT_VERSION) {
@@ -203,11 +205,13 @@ bool CheckProRegTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CValid
 
 bool CheckProUpServTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CValidationState& state)
 {
-    AssertLockHeld(cs_main);
+    if (tx.nType != TRANSACTION_PROVIDER_UPDATE_SERVICE) {
+        return state.DoS(100, false, REJECT_INVALID, "bad-protx-type");
+    }
 
     CProUpServTx ptx;
     if (!GetTxPayload(tx, ptx)) {
-        return state.DoS(100, false, REJECT_INVALID, "bad-tx-payload");
+        return state.DoS(100, false, REJECT_INVALID, "bad-protx-payload");
     }
 
     if (ptx.nVersion > CProRegTx::CURRENT_VERSION) {
@@ -255,11 +259,13 @@ bool CheckProUpServTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CVa
 
 bool CheckProUpRegTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CValidationState& state)
 {
-    AssertLockHeld(cs_main);
+    if (tx.nType != TRANSACTION_PROVIDER_UPDATE_REGISTRAR) {
+        return state.DoS(100, false, REJECT_INVALID, "bad-protx-type");
+    }
 
     CProUpRegTx ptx;
     if (!GetTxPayload(tx, ptx)) {
-        return state.DoS(100, false, REJECT_INVALID, "bad-tx-payload");
+        return state.DoS(100, false, REJECT_INVALID, "bad-protx-payload");
     }
 
     if (ptx.nVersion > CProRegTx::CURRENT_VERSION) {
@@ -335,11 +341,13 @@ bool CheckProUpRegTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CVal
 
 bool CheckProUpRevTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CValidationState& state)
 {
-    AssertLockHeld(cs_main);
+    if (tx.nType != TRANSACTION_PROVIDER_UPDATE_REVOKE) {
+        return state.DoS(100, false, REJECT_INVALID, "bad-protx-type");
+    }
 
     CProUpRevTx ptx;
     if (!GetTxPayload(tx, ptx)) {
-        return state.DoS(100, false, REJECT_INVALID, "bad-tx-payload");
+        return state.DoS(100, false, REJECT_INVALID, "bad-protx-payload");
     }
 
     if (ptx.nVersion > CProRegTx::CURRENT_VERSION) {
diff --git a/src/evo/specialtx.cpp b/src/evo/specialtx.cpp
index f73e72c616..cd2a1d0bb7 100644
--- a/src/evo/specialtx.cpp
+++ b/src/evo/specialtx.cpp
@@ -16,9 +16,7 @@
 
 bool CheckSpecialTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CValidationState& state)
 {
-    AssertLockHeld(cs_main);
-
-    if (tx.nVersion < 3 || tx.nType == TRANSACTION_NORMAL)
+    if (tx.nVersion != 3 || tx.nType == TRANSACTION_NORMAL)
         return true;
 
     if (pindexPrev && VersionBitsState(pindexPrev, Params().GetConsensus(), Consensus::DEPLOYMENT_DIP0003, versionbitscache) != THRESHOLD_ACTIVE) {
@@ -38,12 +36,12 @@ bool CheckSpecialTx(const CTransaction& tx, const CBlockIndex* pindexPrev, CVali
         return CheckCbTx(tx, pindexPrev, state);
     }
 
-    return state.DoS(10, false, REJECT_INVALID, "bad-tx-type");
+    return state.DoS(10, false, REJECT_INVALID, "bad-tx-type-check");
 }
 
 bool ProcessSpecialTx(const CTransaction& tx, const CBlockIndex* pindex, CValidationState& state)
 {
-    if (tx.nVersion < 3 || tx.nType == TRANSACTION_NORMAL) {
+    if (tx.nVersion != 3 || tx.nType == TRANSACTION_NORMAL) {
         return true;
     }
 
@@ -57,12 +55,12 @@ bool ProcessSpecialTx(const CTransaction& tx, const CBlockIndex* pindex, CValida
         return true; // nothing to do
     }
 
-    return state.DoS(100, false, REJECT_INVALID, "bad-tx-type");
+    return state.DoS(100, false, REJECT_INVALID, "bad-tx-type-proc");
 }
 
 bool UndoSpecialTx(const CTransaction& tx, const CBlockIndex* pindex)
 {
-    if (tx.nVersion < 3 || tx.nType == TRANSACTION_NORMAL) {
+    if (tx.nVersion != 3 || tx.nType == TRANSACTION_NORMAL) {
         return true;
     }
 
diff --git a/src/primitives/transaction.h b/src/primitives/transaction.h
index cfcd66afe2..c2c2d1d556 100644
--- a/src/primitives/transaction.h
+++ b/src/primitives/transaction.h
@@ -260,7 +260,7 @@ public:
         s << vin;
         s << vout;
         s << nLockTime;
-        if (this->nVersion >= 3 && this->nType != TRANSACTION_NORMAL)
+        if (this->nVersion == 3 && this->nType != TRANSACTION_NORMAL)
             s << vExtraPayload;
     }
 
@@ -339,7 +339,7 @@ struct CMutableTransaction
         READWRITE(vin);
         READWRITE(vout);
         READWRITE(nLockTime);
-        if (this->nVersion >= 3 && this->nType != TRANSACTION_NORMAL) {
+        if (this->nVersion == 3 && this->nType != TRANSACTION_NORMAL) {
             READWRITE(vExtraPayload);
         }
     }
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index d86696cb8b..bc7e58acdd 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -1112,7 +1112,7 @@ public:
              SerializeOutput(s, nOutput);
         // Serialize nLockTime
         ::Serialize(s, txTo.nLockTime);
-        if (txTo.nVersion >= 3 && txTo.nType != TRANSACTION_NORMAL)
+        if (txTo.nVersion == 3 && txTo.nType != TRANSACTION_NORMAL)
             ::Serialize(s, txTo.vExtraPayload);
     }
 };
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index 9021314c47..46b4c4b74c 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -444,7 +444,8 @@ bool CTxMemPool::addUnchecked(const uint256& hash, const CTxMemPoolEntry &entry,
     if (tx.nType == TRANSACTION_PROVIDER_REGISTER) {
         CProRegTx proTx;
         if (!GetTxPayload(tx, proTx)) {
-            assert(false);
+            LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
+            return false;
         }
         mapProTxAddresses.emplace(proTx.addr, tx.GetHash());
         mapProTxPubKeyIDs.emplace(proTx.keyIDOwner, tx.GetHash());
@@ -455,13 +456,15 @@ bool CTxMemPool::addUnchecked(const uint256& hash, const CTxMemPoolEntry &entry,
     } else if (tx.nType == TRANSACTION_PROVIDER_UPDATE_SERVICE) {
         CProUpServTx proTx;
         if (!GetTxPayload(tx, proTx)) {
-            assert(false);
+            LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
+            return false;
         }
         mapProTxAddresses.emplace(proTx.addr, tx.GetHash());
     } else if (tx.nType == TRANSACTION_PROVIDER_UPDATE_REGISTRAR) {
         CProUpRegTx proTx;
         if (!GetTxPayload(tx, proTx)) {
-            assert(false);
+            LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
+            return false;
         }
         mapProTxBlsPubKeyHashes.emplace(proTx.pubKeyOperator.GetHash(), tx.GetHash());
     }
@@ -825,7 +828,8 @@ void CTxMemPool::removeProTxConflicts(const CTransaction &tx)
     if (tx.nType == TRANSACTION_PROVIDER_REGISTER) {
         CProRegTx proTx;
         if (!GetTxPayload(tx, proTx)) {
-            assert(false);
+            LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
+            return;
         }
 
         if (mapProTxAddresses.count(proTx.addr)) {
@@ -842,7 +846,8 @@ void CTxMemPool::removeProTxConflicts(const CTransaction &tx)
     } else if (tx.nType == TRANSACTION_PROVIDER_UPDATE_SERVICE) {
         CProUpServTx proTx;
         if (!GetTxPayload(tx, proTx)) {
-            assert(false);
+            LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
+            return;
         }
 
         if (mapProTxAddresses.count(proTx.addr)) {
@@ -854,7 +859,8 @@ void CTxMemPool::removeProTxConflicts(const CTransaction &tx)
     } else if (tx.nType == TRANSACTION_PROVIDER_UPDATE_REGISTRAR) {
         CProUpRegTx proTx;
         if (!GetTxPayload(tx, proTx)) {
-            assert(false);
+            LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
+            return;
         }
 
         removeProTxPubKeyConflicts(tx, proTx.pubKeyOperator);
@@ -1142,8 +1148,10 @@ bool CTxMemPool::existsProviderTxConflict(const CTransaction &tx) const {
     LOCK(cs);
     if (tx.nType == TRANSACTION_PROVIDER_REGISTER) {
         CProRegTx proTx;
-        if (!GetTxPayload(tx, proTx))
-            assert(false);
+        if (!GetTxPayload(tx, proTx)) {
+            LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
+            return true; // i.e. can't decode payload == conflict
+        }
         if (mapProTxAddresses.count(proTx.addr) || mapProTxPubKeyIDs.count(proTx.keyIDOwner) || mapProTxBlsPubKeyHashes.count(proTx.pubKeyOperator.GetHash()))
             return true;
         if (!proTx.collateralOutpoint.hash.IsNull() && mapProTxCollaterals.count(proTx.collateralOutpoint))
@@ -1151,14 +1159,18 @@ bool CTxMemPool::existsProviderTxConflict(const CTransaction &tx) const {
         return false;
     } else if (tx.nType == TRANSACTION_PROVIDER_UPDATE_SERVICE) {
         CProUpServTx proTx;
-        if (!GetTxPayload(tx, proTx))
-            assert(false);
+        if (!GetTxPayload(tx, proTx)) {
+            LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
+            return true; // i.e. can't decode payload == conflict
+        }
         auto it = mapProTxAddresses.find(proTx.addr);
         return it != mapProTxAddresses.end() && it->second != proTx.proTxHash;
     } else if (tx.nType == TRANSACTION_PROVIDER_UPDATE_REGISTRAR) {
         CProUpRegTx proTx;
-        if (!GetTxPayload(tx, proTx))
-            assert(false);
+        if (!GetTxPayload(tx, proTx)) {
+            LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
+            return true; // i.e. can't decode payload == conflict
+        }
         auto it = mapProTxBlsPubKeyHashes.find(proTx.pubKeyOperator.GetHash());
         return it != mapProTxBlsPubKeyHashes.end() && it->second != proTx.proTxHash;
     }
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 9e88f53646..3ac1434b6b 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -2975,7 +2975,7 @@ bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, bool ov
         coinControl.Select(txin.prevout);
 
     int nExtraPayloadSize = 0;
-    if (tx.nVersion >= 3 && tx.nType != TRANSACTION_NORMAL)
+    if (tx.nVersion == 3 && tx.nType != TRANSACTION_NORMAL)
         nExtraPayloadSize = (int)tx.vExtraPayload.size();
 
     CReserveKey reservekey(this);