Came across an issue with this post: https://lemmy.ml/post/9922111
When viewed in browser it’s a scene from Star Trek about beards, when viewed in Avelon though it’s a video of chinchilla’s dancing and waving their butts about.
Happens each time the post loads, in both the main feed and the post view itself.
On further discussion with other affected users it seems this is due to the original post being edited. Seems it displays fine for web UI users, but not most apps.