ReplayGain isn't re-calculated when changing item in playlist with gapless playback enabled

Provide following Information:

• mpv version: 0.32.0-810-gf85de9e6d6
• Linux Distribution: Arch
• Source of the mpv binary: mpv-full-build AUR package

When playing multiple files in a playlist, it seems like the first file's replaygain is applied to everything, instead of the replaygain for each file being applied when that file is played.

For example, file 1:

mpv -v --no-config --replaygain=track ./1.mkv 2>&1 | grep -i replay
[cplayer] Command line options: '-v' '--no-config' '--replaygain=track' './1.mkv'
[cplayer] Setting option 'replaygain' = 'track' (flags = 8)
[cplayer] Replaygain: Track=5.330000/0.314455 Album=5.330000/0.314455
[cplayer] Applying replay-gain: 1.847141

file 2:

mpv -v --no-config --replaygain=track ./2.mkv 2>&1 | grep -i replay
[cplayer] Command line options: '-v' '--no-config' '--replaygain=track' './2.mkv'
[cplayer] Setting option 'replaygain' = 'track' (flags = 8)
[cplayer] Replaygain: Track=-4.150000/0.647406 Album=-4.150000/0.647406
[cplayer] Applying replay-gain: 0.620155

But if I play both and manually do playlist-next, the only output is:

mpv -v --no-config --replaygain=track ./1.mkv ./2.mkv 2>&1 | grep -i replay
[cplayer] Command line options: '-v' '--no-config' '--replaygain=track' './1.mkv' './2.mkv'
[cplayer] Setting option 'replaygain' = 'track' (flags = 8)
[cplayer] Replaygain: Track=5.330000/0.314455 Album=5.330000/0.314455
[cplayer] Applying replay-gain: 1.847141

and the second file is too loud.

Full log
https://0x0.st/i5zk.txt

Reproduce the issue with the provided mpv commands and compare the replaygain output for standalone files versus playlist-next. Trace where replaygain state is updated when changing playlist items; done means each file applies its own track gain during gapless playback, with tests or logs confirming the second file is no longer too loud.