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)?  
{"change_type", RPCArg::Type::STR, RPCArg::DefaultHint{"set by -changetype"}, "The output type to use. Only valid if change_address is not specified. Options are \"legacy\", \"p2sh-segwit\", \"bech32\" and \"bech32m\"."},
                    {"fee_rate", RPCArg::Type::AMOUNT, RPCArg::DefaultHint{"not set, fall back to wallet fee estimation"}, "Specify a fee rate in " + CURRENCY_ATOM + "/vB.", RPCArgOptions{.also_positional = true}},
                    {"include_watching", RPCArg::Type::BOOL, RPCArg::DefaultHint{"true for watch-only wallets, otherwise false"}, "Also select inputs which are watch only.\n"
                                          "Only solvable inputs can be used. Watch-only destinations are solvable if the public key and/or output script was imported,\n"
                                          "e.g. with 'importpubkey' or 'importmulti' with the 'pubkeys' or 'desc' field."},
                    {"inputs", RPCArg::Type::ARR, RPCArg::Default{UniValue::VARR}, "Specify inputs instead of adding them automatically. A JSON array of JSON objects",
                        {
                            {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The transaction id"},
                            {"vout", RPCArg::Type::NUM, RPCArg::Optional::NO, "The output number"},
                            {"sequence", RPCArg::Type::NUM, RPCArg::Optional::NO, "The sequence number"},
                            {"weight", RPCArg::Type::NUM, RPCArg::DefaultHint{"Calculated from wallet and solving data"}, "The maximum weight for this input, "
                                        "including the weight of the outpoint and sequence number. "
                                        "Note that signature sizes are not guaranteed to be consistent, "
                                        "so the maximum DER signatures size of 73 bytes should be used when considering ECDSA signatures."
                                        "Remember to convert serialized sizes to weight units when necessary."},
                        },
                    },
                    {"locktime", RPCArg::Type::NUM, RPCArg::Default{0}, "Raw locktime. Non-0 value also locktime-activates inputs"},
                    {"lock_unspents", RPCArg::Type::BOOL, RPCArg::Default{false}, "Lock selected unspent outputs"},
                    {"psbt", RPCArg::Type::BOOL,  RPCArg::DefaultHint{"automatic"}, "Always return a PSBT, implies add_to_wallet=false."},
                    {"subtract_fee_from_outputs", RPCArg::Type::ARR, RPCArg::Default{UniValue::VARR}, "Outputs to subtract the fee from, specified as integer indices.\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."},
                        },
                    },
                },
                FundTxDoc()),