If someone boost a PeerTube video, it embeds it in the Akkoma-fe frontend but then fails to show the video preview with a “No video with supported format and MIME type found.” error.
It looks a bit like Akkoma is trying and failing to mirror the Peertube video on the media-proxy and this is what it causing the issue.
I think it would be worthwhile to add a specific exception for Peertube videos and only media-proxy the preview image or so from the video, but not the video itself.