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.

{
    LOCK(cs_wallet);
    
    SetMinVersion(FEATURE_HD);
    
    
    
    CHDChain newHdChain;
    newHdChain.masterKeyID = pubkey.GetID();
    SetHDChain(newHdChain, false);
    return true;
}
bool CWallet::SetHDChain(const CHDChain& chain, bool memonly)
{
    LOCK(cs_wallet);
    if (!memonly && !CWalletDB(strWalletFile).WriteHDChain(chain))
        throw runtime_error(std::string(__func__) + ": writing chain failed");
    hdChain = chain;
    return true;
}
bool CWallet::IsHDEnabled()
{
    return !hdChain.masterKeyID.IsNull();
}
int64_t CWalletTx::GetTxTime() const