Intermittant failure during playback on Amazon Fire TV v1

I’ve been using a Fire TV v1 for some time with no issues however over the last week or so some videos (mkv files) have been stopping intermittantly, typically after 10+ minutes of playback but it doesn’t seem deterministic.

I’ve not changed anything and my Fire TV stick in another room plays the same files without issue.

I’ve uploaded a debug log here and would be extremely grateful if anyone can offer any pointers?

Thanks
Simon