Overlapping vtt subtitle does not end at specified time

[hisel-sabermetrics]

mpv Information

mpv v0.40.0 Copyright © 2000-2025 mpv/MPlayer/mplayer2 projects
libplacebo version: v7.351.0
FFmpeg version: 7.1.1
FFmpeg library versions:
   libavcodec      61.19.101
   libavdevice     61.3.100
   libavfilter     10.4.100
   libavformat     61.7.100
   libavutil       59.39.100
   libswresample   5.3.100
   libswscale      8.3.100

Other Information

- macOS version: macOS 15.5 (24F74)
- Source of mpv: Brew
- Latest known working version:
- Issue started after the following happened:

Reproduction Steps

1. Have a video track with longer audio track
2. Create a vtt file
3. Add an entry to the vtt after the end time of the video track
4. Add a second entry to the vtt file with start time within the first entry and end time after the first entry
5. Remux the vtt file with the video and audio track

Expected Behavior

The subtitle ends at the specified time in the file

Actual Behavior

The first subtitle entry got extended to the end of the second entry

Log File

output.txt

Sample Files

No response

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

• [x] I tested with the latest mpv version to validate that the issue is not already fixed.
• [x] I provided all required information including system and mpv version.
• [x] 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.
• [x] I produced the log file while the behaviors described in "Actual Behavior" were actively observed.
• [x] I attached the full, untruncated log file.
• [x] I attached the backtrace in the case of a crash.