Since last update some videos launch with wrong projection when streamed from supported webpage. Before the update the videos were playing in proper projection (sbs-180).
It doesn't happen for all videos on the webpage.
I've downloaded some of the messed up videos. I noticed that the very first frame of them is actually mono. From frame 2 onwards they switch to sbs. I'm not sure what Play'a does exactly, but it SEEMS like it detects the resolution for the first frame, cuts it in half, and that uses it for all subsequent frames. Because of that all further frames are actually using only half of what they should, and the projection is a mess. When you close one eye you can see that the frame the other eye sees is cut in half, which seems like that's the issue - Play'a plays the video in sbs-180 but cut in half.
As long as the file is downloaded it can be used with mono-180 setting (for downloaded files it's possible to change the projection) which is still wrong, as the vids are sbs-180. But at least it looks acceptable, and can be used as workaround... The problem is the projection cannot be set manually when streaming, so this completely breaks the content!
There is a thread on steam that has been ignored for over a month, where an user listed a video which has exactly the same issue (first frame is mono) https://steamcommunity.com/app/1114420/discussions/0/4333104322148534117/
All other players that I tested support those videos with initial frame in different resolution without a hitch.
I have this same issue for months. Using Quest 3 via link cable, Version 2.2.11 off the quest store. Mostly affects higher quality videos. 6k-8k. What puzzles me is some videos will display horribly in 8k but fine in 5k.