Indentation in cfg inside a macro increases on each fmt

Each time the following macro is formatted, the text inside the cfg becomes increasingly indented.

Reproducible playground: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=e4c809502358b19465decfbac2d40a08

Happens at on all versions I've tried — both current nightly (rustfmt 1.4.38-nightly (29b12480 2021-10-25)) and stable, (rustfmt 1.4.37-stable (09c42c45 2021-10-18))

Details

Given the input:

macro_rules! check_runtime_prefix {
    ($runtime_feat:literal, $runtime_crate:literal) => {
        #[cfg(all(
            any(feature = $runtime_feat, feature = $runtime_crate),
            not(all(feature = $runtime_feat, feature = $runtime_crate)),
        ))]
        compile_error!(concat!(
            "Please enable the `",
            $runtime_feat,
            "` feature rather than enabling `",
            $runtime_crate,
            "` directly",
        ));
    };
}

After formatting, the rest of the macro is unchanged, but the cfg block becomes

macro_rules! check_runtime_prefix {
    ($runtime_feat:literal, $runtime_crate:literal) => {
        #[cfg(all(
                    any(feature = $runtime_feat, feature = $runtime_crate),
                    not(all(feature = $runtime_feat, feature = $runtime_crate)),
                ))]
        compile_error!(<snip>);
    };
}

After formatting again, the cfg block becomes

macro_rules! check_runtime_prefix {
    ($runtime_feat:literal, $runtime_crate:literal) => {
        #[cfg(all(
                            any(feature = $runtime_feat, feature = $runtime_crate),
                            not(all(feature = $runtime_feat, feature = $runtime_crate)),
                        ))]
        compile_error!(<snip>);
    };
}

Etc.

Start with the linked Rust Playground example and run rustfmt repeatedly on the provided macro. Compare the cfg block after each run and use the reproducer to define done: formatting should produce stable indentation instead of increasing it on every pass.