When a pass of CreateTransaction fails to select enough bitcoin to meet the nFeeNeeded the next pass through may select a far smaller collection of inputs.  Currently it will continue to use the old fee amount based on the larger set of inputs, which can cause a non-trivial over-payment.

This may be the cause of the behavior reported here: https://www.reddit.com/r/Bitcoin/comments/5ltw5n/bitcoin_core_v0131_sends_enormously_high_fee/

Long ago fixing this was tricky due to a catch-22 between signing the transaction and knowing how much fee was required.  But after #9465 the whole algorithm will run using a dummy signature, so when there is already a change output fixing up the fee after finding a sufficient transaction should be a matter of a ~2 line change.

{
    CWalletDB walletdb(strWalletFile);
    CAccount account;
    walletdb.ReadAccount(strAccount, account);
    if (!bForceNew) {
        if (!account.vchPubKey.IsValid())
            bForceNew = true;
        else {
            
            CScript scriptPubKey = GetScriptForDestination(account.vchPubKey.GetID());
            for (map<uint256, CWalletTx>::iterator it = mapWallet.begin();
                 it != mapWallet.end() && account.vchPubKey.IsValid();
                 ++it)
                BOOST_FOREACH(const CTxOut& txout, (*it).second.tx->vout)
                    if (txout.scriptPubKey == scriptPubKey) {
                        bForceNew = true;
                        break;
                    }
        }
    }
    
    if (bForceNew) {
        if (!GetKeyFromPool(account.vchPubKey))
            return false;