`slang` doesn't work within `profile-cond`

mpv Information

mpv --version
mpv v0.40.0-30-g5ba7ee513 Copyright © 2000-2025 mpv/MPlayer/mplayer2 projects
 built on Mar 29 2025 00:11:15
libplacebo version: v7.350.0 (v7.349.0-62-g563ea4a-dirty)
FFmpeg version: N-119073-g2657e1679
FFmpeg library versions:
   libavcodec      62.0.100
   libavdevice     62.0.100
   libavfilter     11.0.100
   libavformat     62.0.100
   libavutil       60.0.100
   libswresample   6.0.100
   libswscale      9.0.100

Other Information

- Windows version: 10.0.19044.5608
- GPU model, driver and version: Not relevant.
- Source of mpv: Sourceforge.
- Latest known working version: I'm not aware whether this ever worked before, or not.
- Issue started after the following happened: Testing.

Reproduction Steps

sid/sub 1 works within profile-cond though, which's odd. Using show-text "${slang}" shows the right value, but it seems like it's not actioned on.

Expected Behavior

Should work, works as expected when passing --slang='en,eng'.

Actual Behavior

Doesn't work. Maybe related to #14388.

Log File

mpv.log

Sample Files

mpv.conf

[net]
profile-cond=demuxer_via_network or stream_path == '-'
slang='en,eng'

I carefully read all instruction and confirm that I did the following:

• I tested with the latest mpv version to validate that the issue is not already fixed.
• I provided all required information including system and mpv version.
• I produced the log file with the exact same set of files, parameters, and conditions used in "Reproduction Steps", with the addition of --log-file=output.txt.
• I produced the log file while the behaviors described in "Actual Behavior" were actively observed.
• I attached the full, untruncated log file.
• I attached the backtrace in the case of a crash.

Start by reproducing the issue with the provided mpv.conf, comparing slang inside profile-cond with --slang='en,eng' and the working sid/sub settings. Use the attached mpv.log to trace the behavior; done means slang set by the profile-cond section takes effect as it does on the command line.