If the beatmap has no music, the replay will not play.

[Andrey94-1]

It's easy to check, just delete the music from the beatmap folder, make a replay and f2.
I found this error on this beatmap↓.
https://osu.ppy.sh/beatmapsets/30229#osu/121594

[abstrakt8]

True because I'm calculating the duration of the replay from the underlying mp3 file, but I think I could instead use the max time value from the replay instead in case the mp3 file is missing.