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.

}
    if (GetBoolArg("-upgradewallet", fFirstRun))
    {
        int nMaxVersion = GetArg("-upgradewallet", 0);
        if (nMaxVersion == 0) 
        {
            LogPrintf("Performing wallet upgrade to %i\n", FEATURE_LATEST);
            nMaxVersion = CLIENT_VERSION;
            walletInstance->SetMinVersion(FEATURE_LATEST); 
        }
        else
            LogPrintf("Allowing wallet upgrade up to %i\n", nMaxVersion);
        if (nMaxVersion < walletInstance->GetVersion())
        {
            InitError(_("Cannot downgrade wallet"));
            return NULL;
        }
        walletInstance->SetMaxVersion(nMaxVersion);
    }
    if (fFirstRun)
    {
        
        if (GetBoolArg("-usehd", DEFAULT_USE_HD_WALLET) && !walletInstance->IsHDEnabled()) {
            
            CPubKey masterPubKey = walletInstance->GenerateNewHDMasterKey();
            if (!walletInstance->SetHDMasterKey(masterPubKey))
                throw std::runtime_error(std::string(__func__) + ": Storing master key failed");
        }
        CPubKey newDefaultKey;
        if (walletInstance->GetKeyFromPool(newDefaultKey)) {