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.

{
        pwallet = pwalletIn;
        MarkDirty();
    }
    
    CAmount GetDebit(const isminefilter& filter) const;
    CAmount GetCredit(const isminefilter& filter) const;
    CAmount GetImmatureCredit(bool fUseCache=true) const;
    CAmount GetAvailableCredit(bool fUseCache=true) const;
    CAmount GetImmatureWatchOnlyCredit(const bool& fUseCache=true) const;
    CAmount GetAvailableWatchOnlyCredit(const bool& fUseCache=true) const;
    CAmount GetChange() const;
    void GetAmounts(std::list<COutputEntry>& listReceived,
                    std::list<COutputEntry>& listSent, CAmount& nFee, std::string& strSentAccount, const isminefilter& filter) const;
    void GetAccountAmounts(const std::string& strAccount, CAmount& nReceived,
                           CAmount& nSent, CAmount& nFee, const isminefilter& filter) const;
    bool IsFromMe(const isminefilter& filter) const
    {
        return (GetDebit(filter) > 0);
    }
    
    bool IsEquivalentTo(const CWalletTx& tx) const;
    bool InMempool() const;
    bool IsTrusted() const;
    int64_t GetTxTime() const;
    int GetRequestCount() const;
    bool RelayWalletTransaction(CConnman* connman);
    std::set<uint256> GetConflicts() const;
};
class COutput