I downloaded your video and sometimes I get the scrabbing issue too. It doesn't happen with other videos on my computer, so maybe it is something related to the video codecs? I normally use h.264, and it works fine for me.
Would you be able to provide which encoding settings you use? I am also rendering out h.264 but through blender and every file mp4 I have seems to be bugging out haha. Hoping to narrow down the issue a bit.
