A specific MP4 file is not playable with avfoundation in iOS
The original video is an old, interlaced format.  At least, according to the line that says, &quot;smpte170m/bt470bg/bt709.&quot;  The SMPTE standard is available for purchase here, but you can tell from the summary that it's interlaced.
The second ffmpeg command is copying the format without re-encoding, or handling the interlacing, which isn’t supported on iOS.  The first set of commands work because the video is being re-encoded. Whether or not the video is automatically being de-interlaced, I can’t say without seeing, but I doubt it.  See my answer to this question to judge for yourself.