[FFmpeg-user] File metadata in m4a causing player problem?

[Budge]

I have a set of m4a audio files which I can play but on which the
progress bar does not work.  If I select anywhere along the progress bar
playing starts again from the beginning.

The only difference I can see when using ffprobe to examine the metadata
is that files which have a creation_time set have a non functioning
progress bar problem.

Files which do NOT have the Stream metadata :creation_time, play correctly.

The metadata is shown:-

Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo,
fltp, 319 kb/s (default)
    Metadata:
      creation_time   : 1970-01-01T00:00:00.000000Z
      handler_name    : SoundHandler

This creation_time seems to me like a default not the actual time when
file was created and may be the cause of the player problem.

What I wish to do is remove the tag:
creation_time   : 1970-01-01T00:00:00.000000Z

I confess using ffmpeg to achieve this, if indeed this is the correct
tool, is well beyond my ability and I am seeking help here.  I
appreciate this still may not fix my problem but I must try and
eliminate possible causes and this is one possible fix.  Can anybody
help please.

Budgie