comment added

src/cc/import.cpp

@@ -415,7 +415,7 @@ bool Eval::ImportCoin(const std::vector<uint8_t> params,const CTransaction &impo
         return Invalid("invalid-params");
     // Control all aspects of this transaction
     // It should not be at all malleable
-    if (MakeImportCoinTransaction(proof, burnTx, payouts, importTx.nExpiryHeight).GetHash() != importTx.GetHash())
+    if (MakeImportCoinTransaction(proof, burnTx, payouts, importTx.nExpiryHeight).GetHash() != importTx.GetHash())  // ExistsImportTombstone prevents from duplication
         return Invalid("non-canonical");
     // burn params
     if (!UnmarshalBurnTx(burnTx, targetSymbol, &targetCcid, payoutsHash, rawproof))