I am relaying a privacy issue for Bitcoin Core that was [reported on r/Bitcoin](https://reddit.com/r/Bitcoin/comments/klk2wh) (Reddit).

The [message](https://pastebin.com/raw/ptFQityt) was:

- _Using coin control_
- _Custom change address_

_When one clicks the increase transaction fee button, it adds another input rather than increasing the fee by reducing the change output. Major privacy leak since you have no control of the input used._

From that it sounds like the observed behavior is that the replacement transaction includes an additional UTXO that was not chosen by the user, even though the transaction was composed as a Coin Control transaction.

So I'm assuming the expected behavior would be for Bitcoin Core to remember that this OUTPUT was actually a Custom Change Address and to then lower the amount of that OUTPUT by the amount needed for the fee bump.

And, now that I am thinking of this, isn't there the expectation that if my initial transaction was done using Coin Control, and then if my fee bump (RBF) needs another UTXO input to cover the increase in fee, that Coin Selection for that will occur (regardless of whether or not the change address was a Custom Change Address)?  
{
    return RPCHelpMan{"sendtoaddress",
                "\nSend an amount to a given address." +
        HELP_REQUIRING_PASSPHRASE,
                {
                    {"address", RPCArg::Type::STR, RPCArg::Optional::NO, "The bitcoin address to send to."},
                    {"amount", RPCArg::Type::AMOUNT, RPCArg::Optional::NO, "The amount in " + CURRENCY_UNIT + " to send. eg 0.1"},
                    {"comment", RPCArg::Type::STR, RPCArg::Optional::OMITTED, "A comment used to store what the transaction is for.\n"
                                         "This is not part of the transaction, just kept in your wallet."},
                    {"comment_to", RPCArg::Type::STR, RPCArg::Optional::OMITTED, "A comment to store the name of the person or organization\n"
                                         "to which you're sending the transaction. This is not part of the \n"
                                         "transaction, just kept in your wallet."},
                    {"subtractfeefromamount", RPCArg::Type::BOOL, RPCArg::Default{false}, "The fee will be deducted from the amount being sent.\n"
                                         "The recipient will receive less bitcoins than you enter in the amount field."},
                    {"replaceable", RPCArg::Type::BOOL, RPCArg::DefaultHint{"wallet default"}, "Signal that this transaction can be replaced by a transaction (BIP 125)"},
                    {"conf_target", RPCArg::Type::NUM, RPCArg::DefaultHint{"wallet -txconfirmtarget"}, "Confirmation target in blocks"},
                    {"estimate_mode", RPCArg::Type::STR, RPCArg::Default{"unset"}, "The fee estimate mode, must be one of (case insensitive):\n"
                     "\"" + FeeModes("\"\n\"") + "\""},
                    {"avoid_reuse", RPCArg::Type::BOOL, RPCArg::Default{true}, "(only available if avoid_reuse wallet flag is set) Avoid spending from dirty addresses; addresses are considered\n"
                                         "dirty if they have previously been used in a transaction. If true, this also activates avoidpartialspends, grouping outputs by their addresses."},
                    {"fee_rate", RPCArg::Type::AMOUNT, RPCArg::DefaultHint{"not set, fall back to wallet fee estimation"}, "Specify a fee rate in " + CURRENCY_ATOM + "/vB."},
                    {"verbose", RPCArg::Type::BOOL, RPCArg::Default{false}, "If true, return extra information about the transaction."},
                },
                {
                    RPCResult{"if verbose is not set or set to false",
                        RPCResult::Type::STR_HEX, "txid", "The transaction id."
                    },
                    RPCResult{"if verbose is set to true",
                        RPCResult::Type::OBJ, "", "",
                        {