diff --git a/src/test/test_dash.cpp b/src/test/test_dash.cpp
index 7bc3f7e9f7..521d8a422f 100644
--- a/src/test/test_dash.cpp
+++ b/src/test/test_dash.cpp
@@ -50,11 +50,16 @@ BasicTestingSetup::BasicTestingSetup(const std::string& chainName)
         fPrintToDebugLog = false; // don't want to write to debug.log file
         fCheckBlockIndex = true;
         SelectParams(chainName);
+        evoDb = new CEvoDB(1 << 20, true, true);
+        deterministicMNManager = new CDeterministicMNManager(*evoDb);
         noui_connect();
 }
 
 BasicTestingSetup::~BasicTestingSetup()
 {
+        delete deterministicMNManager;
+        delete evoDb;
+
         ECC_Stop();
         g_connman.reset();
 }
@@ -70,10 +75,8 @@ TestingSetup::TestingSetup(const std::string& chainName) : BasicTestingSetup(cha
         boost::filesystem::create_directories(pathTemp);
         ForceSetArg("-datadir", pathTemp.string());
         mempool.setSanityCheck(1.0);
-        evoDb = new CEvoDB(1 << 20, true, true);
         pblocktree = new CBlockTreeDB(1 << 20, true);
         pcoinsdbview = new CCoinsViewDB(1 << 23, true);
-        deterministicMNManager = new CDeterministicMNManager(*evoDb);
         llmq::InitLLMQSystem(*evoDb);
         pcoinsTip = new CCoinsViewCache(pcoinsdbview);
         InitBlockIndex(chainparams);
@@ -98,10 +101,8 @@ TestingSetup::~TestingSetup()
         UnloadBlockIndex();
         delete pcoinsTip;
         llmq::DestroyLLMQSystem();
-        delete deterministicMNManager;
         delete pcoinsdbview;
         delete pblocktree;
-        delete evoDb;
         boost::filesystem::remove_all(pathTemp);
 }
 
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index 46b4c4b74c..56437de93a 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -447,6 +447,9 @@ bool CTxMemPool::addUnchecked(const uint256& hash, const CTxMemPoolEntry &entry,
             LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
             return false;
         }
+        if (!proTx.collateralOutpoint.hash.IsNull()) {
+            mapProTxRefs.emplace(tx.GetHash(), proTx.collateralOutpoint.hash);
+        }
         mapProTxAddresses.emplace(proTx.addr, tx.GetHash());
         mapProTxPubKeyIDs.emplace(proTx.keyIDOwner, tx.GetHash());
         mapProTxBlsPubKeyHashes.emplace(proTx.pubKeyOperator.GetHash(), tx.GetHash());
@@ -459,6 +462,7 @@ bool CTxMemPool::addUnchecked(const uint256& hash, const CTxMemPoolEntry &entry,
             LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
             return false;
         }
+        mapProTxRefs.emplace(proTx.proTxHash, tx.GetHash());
         mapProTxAddresses.emplace(proTx.addr, tx.GetHash());
     } else if (tx.nType == TRANSACTION_PROVIDER_UPDATE_REGISTRAR) {
         CProUpRegTx proTx;
@@ -466,7 +470,15 @@ bool CTxMemPool::addUnchecked(const uint256& hash, const CTxMemPoolEntry &entry,
             LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
             return false;
         }
+        mapProTxRefs.emplace(proTx.proTxHash, tx.GetHash());
         mapProTxBlsPubKeyHashes.emplace(proTx.pubKeyOperator.GetHash(), tx.GetHash());
+    } else if (tx.nType == TRANSACTION_PROVIDER_UPDATE_REVOKE) {
+        CProUpRevTx proTx;
+        if (!GetTxPayload(tx, proTx)) {
+            LogPrintf("%s: ERROR: Invalid transaction payload, tx: %s", __func__, tx.ToString());
+            return false;
+        }
+        mapProTxRefs.emplace(proTx.proTxHash, tx.GetHash());
     }
 
     return true;
@@ -644,11 +656,25 @@ void CTxMemPool::removeUnchecked(txiter it, MemPoolRemovalReason reason)
     } else
         vTxHashes.clear();
 
+    auto eraseProTxRef = [&](const uint256& proTxHash, const uint256& txHash) {
+        auto its = mapProTxRefs.equal_range(proTxHash);
+        for (auto it = its.first; it != its.second;) {
+            if (it->second == txHash) {
+                it = mapProTxRefs.erase(it);
+            } else {
+                ++it;
+            }
+        }
+    };
+
     if (it->GetTx().nType == TRANSACTION_PROVIDER_REGISTER) {
         CProRegTx proTx;
         if (!GetTxPayload(it->GetTx(), proTx)) {
             assert(false);
         }
+        if (!proTx.collateralOutpoint.IsNull()) {
+            eraseProTxRef(it->GetTx().GetHash(), proTx.collateralOutpoint.hash);
+        }
         mapProTxAddresses.erase(proTx.addr);
         mapProTxPubKeyIDs.erase(proTx.keyIDOwner);
         mapProTxBlsPubKeyHashes.erase(proTx.pubKeyOperator.GetHash());
@@ -658,13 +684,21 @@ void CTxMemPool::removeUnchecked(txiter it, MemPoolRemovalReason reason)
         if (!GetTxPayload(it->GetTx(), proTx)) {
             assert(false);
         }
+        eraseProTxRef(proTx.proTxHash, it->GetTx().GetHash());
         mapProTxAddresses.erase(proTx.addr);
     } else if (it->GetTx().nType == TRANSACTION_PROVIDER_UPDATE_REGISTRAR) {
         CProUpRegTx proTx;
         if (!GetTxPayload(it->GetTx(), proTx)) {
             assert(false);
         }
+        eraseProTxRef(proTx.proTxHash, it->GetTx().GetHash());
         mapProTxBlsPubKeyHashes.erase(proTx.pubKeyOperator.GetHash());
+    } else if (it->GetTx().nType == TRANSACTION_PROVIDER_UPDATE_REVOKE) {
+        CProUpRevTx proTx;
+        if (!GetTxPayload(it->GetTx(), proTx)) {
+            assert(false);
+        }
+        eraseProTxRef(proTx.proTxHash, it->GetTx().GetHash());
     }
 
     totalTxSize -= it->GetTxSize();
@@ -823,8 +857,46 @@ void CTxMemPool::removeProTxCollateralConflicts(const CTransaction &tx, const CO
     }
 }
 
+void CTxMemPool::removeProTxSpentCollateralConflicts(const CTransaction &tx)
+{
+    // Remove TXs that refer to a MN for which the collateral was spent
+    auto removeSpentCollateralConflict = [&](const uint256& proTxHash) {
+        // Can't use equal_range here as every call to removeRecursive might invalidate iterators
+        while (true) {
+            auto it = mapProTxRefs.find(proTxHash);
+            if (it == mapProTxRefs.end()) {
+                break;
+            }
+            auto conflictIt = mapTx.find(it->second);
+            if (conflictIt != mapTx.end()) {
+                removeRecursive(conflictIt->GetTx(), MemPoolRemovalReason::CONFLICT);
+            } else {
+                // Should not happen as we track referencing TXs in addUnchecked/removeUnchecked.
+                // But lets be on the safe side and not run into an endless loop...
+                LogPrintf("%s: ERROR: found invalid TX ref in mapProTxRefs, proTxHash=%s, txHash=%s", __func__, proTxHash.ToString(), it->second.ToString());
+                mapProTxRefs.erase(it);
+            }
+        }
+    };
+    auto mnList = deterministicMNManager->GetListAtChainTip();
+    for (const auto& in : tx.vin) {
+        auto collateralIt = mapProTxCollaterals.find(in.prevout);
+        if (collateralIt != mapProTxCollaterals.end()) {
+            // These are not yet mined ProRegTxs
+            removeSpentCollateralConflict(collateralIt->second);
+        }
+        auto dmn = mnList.GetMNByCollateral(in.prevout);
+        if (dmn) {
+            // These are updates refering to a mined ProRegTx
+            removeSpentCollateralConflict(dmn->proTxHash);
+        }
+    }
+}
+
 void CTxMemPool::removeProTxConflicts(const CTransaction &tx)
 {
+    removeProTxSpentCollateralConflicts(tx);
+
     if (tx.nType == TRANSACTION_PROVIDER_REGISTER) {
         CProRegTx proTx;
         if (!GetTxPayload(tx, proTx)) {
diff --git a/src/txmempool.h b/src/txmempool.h
index 81ceedc53d..1362c80643 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -534,6 +534,7 @@ private:
     typedef std::map<uint256, std::vector<CSpentIndexKey> > mapSpentIndexInserted;
     mapSpentIndexInserted mapSpentInserted;
 
+    std::multimap<uint256, uint256> mapProTxRefs; // proTxHash -> transaction (all TXs that refer to an existing proTx)
     std::map<CService, uint256> mapProTxAddresses;
     std::map<CKeyID, uint256> mapProTxPubKeyIDs;
     std::map<uint256, uint256> mapProTxBlsPubKeyHashes;
@@ -584,6 +585,7 @@ public:
     void removeProTxPubKeyConflicts(const CTransaction &tx, const CKeyID &keyId);
     void removeProTxPubKeyConflicts(const CTransaction &tx, const CBLSPublicKey &pubKey);
     void removeProTxCollateralConflicts(const CTransaction &tx, const COutPoint &collateralOutpoint);
+    void removeProTxSpentCollateralConflicts(const CTransaction &tx);
     void removeProTxConflicts(const CTransaction &tx);
     void removeForBlock(const std::vector<CTransactionRef>& vtx, unsigned int nBlockHeight);