diff --git a/src/bitcoin-tx.cpp b/src/bitcoin-tx.cpp
index 437acac64..4632977eb 100644
--- a/src/bitcoin-tx.cpp
+++ b/src/bitcoin-tx.cpp
@@ -499,7 +499,7 @@ static void MutateTxSign(CMutableTransaction& tx, const string& flagStr)
 
         // ... and merge in other signatures:
         BOOST_FOREACH(const CTransaction& txv, txVariants) {
-            txin.scriptSig = CombineSignatures(prevPubKey, mergedTx, i, amount, txin.scriptSig, txv.vin[i].scriptSig);
+            txin.scriptSig = CombineSignatures(prevPubKey, MutableTransactionSignatureChecker(&mergedTx, i, amount), txin.scriptSig, txv.vin[i].scriptSig);
         }
         if (!VerifyScript(txin.scriptSig, prevPubKey, STANDARD_SCRIPT_VERIFY_FLAGS, MutableTransactionSignatureChecker(&mergedTx, i, amount)))
             fComplete = false;
diff --git a/src/main.cpp b/src/main.cpp
index b4cef6e40..d5e843b97 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1119,12 +1119,12 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
     {
         COutPoint outpoint = txin.prevout;
         // A respend is a tx that conflicts with a member of the pool
-        auto itConflicting = pool.mapNextTx.find(txin.prevout);
+        auto itConflicting = pool.mapNextTx.find(outpoint);
         if (itConflicting != pool.mapNextTx.end())
         {
             fRespend = true;
             // Relay only one tx per respent outpoint, but not if tx is equivalent to pool member
-            if (!doubleSpendFilter.contains(outpoint) && !tx.IsEquivalentTo(*pool.mapNextTx[outpoint].ptx))
+            if (!doubleSpendFilter.contains(outpoint) && !tx.IsEquivalentTo(*itConflicting->second))
             {
                 relayForOutpoint = outpoint;
                 break;