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)?  
{"outputs", RPCArg::Type::ARR, RPCArg::Optional::NO, "The outputs (key-value pairs), where none of the keys are duplicated.\n"
                            "That is, each address can only appear once and there can only be one 'data' object.\n"
                            "For compatibility reasons, a dictionary, which holds the key-value pairs directly, is also\n"
                            "accepted as second parameter.",
                        OutputsDoc(),
                        RPCArgOptions{.skip_type_check = true}},
                    {"locktime", RPCArg::Type::NUM, RPCArg::Default{0}, "Raw locktime. Non-0 value also locktime-activates inputs"},
                    {"options", RPCArg::Type::OBJ_NAMED_PARAMS, RPCArg::Optional::OMITTED, "",
                        Cat<std::vector<RPCArg>>(
                        {
                            {"add_inputs", RPCArg::Type::BOOL, RPCArg::DefaultHint{"false when \"inputs\" are specified, true otherwise"}, "Automatically include coins from the wallet to cover the target amount.\n"},
                            {"include_unsafe", RPCArg::Type::BOOL, RPCArg::Default{false}, "Include inputs that are not safe to spend (unconfirmed transactions from outside keys and unconfirmed replacement transactions).\n"
                                                          "Warning: the resulting transaction may become invalid if one of the unsafe inputs disappears.\n"
                                                          "If that happens, you will need to fund the transaction with different inputs and republish it."},
                            {"minconf", RPCArg::Type::NUM, RPCArg::Default{0}, "If add_inputs is specified, require inputs with at least this many confirmations."},
                            {"maxconf", RPCArg::Type::NUM, RPCArg::Optional::OMITTED, "If add_inputs is specified, require inputs with at most this many confirmations."},
                            {"changeAddress", RPCArg::Type::STR, RPCArg::DefaultHint{"automatic"}, "The bitcoin address to receive the change"},
                            {"changePosition", RPCArg::Type::NUM, RPCArg::DefaultHint{"random"}, "The index of the change output"},
                            {"change_type", RPCArg::Type::STR, RPCArg::DefaultHint{"set by -changetype"}, "The output type to use. Only valid if changeAddress is not specified. Options are \"legacy\", \"p2sh-segwit\", \"bech32\", and \"bech32m\"."},
                            {"includeWatching", RPCArg::Type::BOOL, RPCArg::DefaultHint{"true for watch-only wallets, otherwise false"}, "Also select inputs which are watch only"},
                            {"lockUnspents", RPCArg::Type::BOOL, RPCArg::Default{false}, "Lock selected unspent outputs"},
                            {"fee_rate", RPCArg::Type::AMOUNT, RPCArg::DefaultHint{"not set, fall back to wallet fee estimation"}, "Specify a fee rate in " + CURRENCY_ATOM + "/vB."},
                            {"feeRate", RPCArg::Type::AMOUNT, RPCArg::DefaultHint{"not set, fall back to wallet fee estimation"}, "Specify a fee rate in " + CURRENCY_UNIT + "/kvB."},
                            {"subtractFeeFromOutputs", RPCArg::Type::ARR, RPCArg::Default{UniValue::VARR}, "The outputs to subtract the fee from.\n"
                                                          "The fee will be equally deducted from the amount of each specified output.\n"
                                                          "Those recipients will receive less bitcoins than you enter in their corresponding amount field.\n"
                                                          "If no outputs are specified here, the sender pays the fee.",
                                {
                                    {"vout_index", RPCArg::Type::NUM, RPCArg::Optional::OMITTED, "The zero-based output index, before a change output is added."},
                                },