"[Error] middleware.go" with opus files / opus files detected wrongly

[Kurami32]

Description
I noticed this error on the log:

2025/08/31 22:52:21 [ERROR] middleware.go:525: GET     | 500 | 10.71.0.6:38940 | admin        | 87ms         | "/api/preview?path=%2FMusic%2FThe_day_that_my_happiness_died.opus&key=1755730443000&source=srv&inline=true"

I don't know exactly why is this error, but I think that is because the opus files are being detected as a video file instead of audio.

Expected behavior
The .opus file should be detected as audio file, and open on the audio player instead of the video player.

Additional context