Stepping frame by frame in debug, the timing info inside the file is fairly consistent with having just 59 frames, somehow the last 20 frames or so are not reachable by normal means.
Is there a player where it fully works? I think the file is broken. When I open in VLC it just freezes on the first frame. In media player classic it shows the entire video but the timeline jumps back at zero halfway through. In the Windows 10 media app it shows the whole video but the timeline reaches the end after maybe a third of the video so seeking with the timeline is even worse. In the classic Windows Media Player the timeline is also completely confused. Some of these players may have less strict requirements on frame-to-timestamp coherence when they just want to playback the video. For frame by frame and accurate time computation Kinovea needs more consistency.
Did you use a particular application or mode on the phone to record it or did you modify it afterwards to trim the endpoints or other post-process? Like maybe a pre-roll or slo-mo feature?