Why are there so many partial content requests in Firefox when streaming mp4 video to Apache?

Edit: It turns out this is actually a Firefox bug.

I have a few videos on my Apache 2.2 server encoded with ffmpeg

with -movflags faststart

and they are streaming fine. However, finding the past buffer line takes a huge amount of time with Firefox (about 30 seconds or more to buffer), while Chrome has no problem.

Chrome shows one network request for mp4 with partial content, but Firefox always shows hundreds of 206 partial content

requests in a row when playing mp4 (open for details):

The most interesting thing is how there is one big request after all the small ones. Is this the point where the video actually starts playing and has it transferred 26MB out of 1.3MB? I'm not sure what's going on here.

Can anyone figure this out? Compare what I get out of this mp4 file here . This does not happen in this file.