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.

}
    }
    return balances;
}
set< set<CTxDestination> > CWallet::GetAddressGroupings()
{
    AssertLockHeld(cs_wallet); 
    set< set<CTxDestination> > groupings;
    set<CTxDestination> grouping;
    BOOST_FOREACH(PAIRTYPE(uint256, CWalletTx) walletEntry, mapWallet)
    {
        CWalletTx *pcoin = &walletEntry.second;
        if (pcoin->tx->vin.size() > 0)
        {
            bool any_mine = false;
            
            BOOST_FOREACH(CTxIn txin, pcoin->tx->vin)
            {
                CTxDestination address;
                if(!IsMine(txin)) 
                    continue;
                if(!ExtractDestination(mapWallet[txin.prevout.hash].tx->vout[txin.prevout.n].scriptPubKey, address))
                    continue;
                grouping.insert(address);
                any_mine = true;
            }
            
            if (any_mine)
            {
               BOOST_FOREACH(CTxOut txout, pcoin->tx->vout)