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.

uiInterface.InitMessage(_("Loading wallet..."));
    int64_t nStart = GetTimeMillis();
    bool fFirstRun = true;
    CWallet *walletInstance = new CWallet(walletFile);
    DBErrors nLoadWalletRet = walletInstance->LoadWallet(fFirstRun);
    if (nLoadWalletRet != DB_LOAD_OK)
    {
        if (nLoadWalletRet == DB_CORRUPT) {
            InitError(strprintf(_("Error loading %s: Wallet corrupted"), walletFile));
            return NULL;
        }
        else if (nLoadWalletRet == DB_NONCRITICAL_ERROR)
        {
            InitWarning(strprintf(_("Error reading %s! All keys read correctly, but transaction data"
                                         " or address book entries might be missing or incorrect."),
                walletFile));
        }
        else if (nLoadWalletRet == DB_TOO_NEW) {
            InitError(strprintf(_("Error loading %s: Wallet requires newer version of %s"), walletFile, _(PACKAGE_NAME)));
            return NULL;
        }
        else if (nLoadWalletRet == DB_NEED_REWRITE)
        {
            InitError(strprintf(_("Wallet needed to be rewritten: restart %s to complete"), _(PACKAGE_NAME)));
            return NULL;
        }
        else {
            InitError(strprintf(_("Error loading %s"), walletFile));
            return NULL;
        }