This is to track the regression introduced in master, which needs fixing for 0.14. See #9240, #9371, etc.
{
    
    LOCK(cs);
    BOOST_FOREACH(const CTxIn &txin, tx.vin) {
        auto it = mapNextTx.find(txin.prevout);
        if (it != mapNextTx.end()) {
            const CTransaction &txConflict = *it->second;
            if (txConflict != tx)
            {
                ClearPrioritisation(txConflict.GetHash());
                removeRecursive(txConflict, MemPoolRemovalReason::CONFLICT);
            }
        }
    }
}
/**
 * Called when a block is connected. Removes from mempool and updates the miner fee estimator.
 */
void CTxMemPool::removeForBlock(const std::vector<CTransactionRef>& vtx, unsigned int nBlockHeight)