I can take a photo from my phone. Essentially I have thick black borders to the left and right of the picture it looks as if plex is squeezing the image.
I have tried casting the same file via solid explorer cast and it is displaying full screen as plex used to, so presumably this has to be a plex configuration issue.
Ok, if the image doesn’t look right, sounds like maybe the aspect ratio is not encoded correctly in your file. Plex will use whatever it is told. Please provide the picture from your phone, and the XML from Plex.
Screenshot of the my video playing via plex on nvidia shield and the info page of the same file.
Plex definitely previously played this file as full screen (with very slim vertical borders) in the same way it played via solid explorer cast this evening.