passing `*-append` option multiple times to the `loadfile` command does not take effect

mpv Information

mpv v0.41.0-536-g174bcec30 Copyright © 2000-2026 mpv/MPlayer/mplayer2 projects
 built on Apr 22 2026 00:05:27
libplacebo version: v7.362.0 (v7.360.0-16-g409c9a8-dirty)
FFmpeg version: N-124075-gd1d873c00
FFmpeg library versions:
   libavcodec      62.30.100
   libavdevice     62.4.100
   libavfilter     11.17.100
   libavformat     62.13.102
   libavutil       60.30.100
   libswresample   6.4.100
   libswscale      9.7.100

Other Information

- Windows version: Win10 22H2
- GPU model, driver and version:
- Source of mpv: https://github.com/zhongfly/mpv-winbuild
- Latest known working version:
- Issue started after the following happened:

Reproduction Steps

This issue exists for all List Options, let's take sub-auto-exts as an example.

• mpv --no-config --idle --force-window --pause --log-file=log.txt
• loadfile sample.mkv replace -1 sub-auto-exts-append=foo,sub-auto-exts-append=bar
• show-text ${sub-auto-exts} 10000

Expected Behavior

both "foo“ and ”bar“ should be appended to sub-auto-exts

Actual Behavior

only ”bar“ was appended.

Log File

log.txt

Sample Files

No response

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

• I tested and confirmed that the issue exists with the latest release version or newer.
• 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 with the loadfile command handling and the processing of repeated list-option assignments such as sub-auto-exts-append. Reproduce the issue with the commands in the report and inspect the attached log; done means both foo and bar remain in sub-auto-exts after the loadfile command.