Bit of a weird one that has started happening for no apparent reason.
My latest version of PMP running on latest version of Windows 10 (HDR On) starts in full screen as you would expect without issue. I can then navigate and play a video file which will play for about 2 or 3 seconds in full screen then Plex will switch into windowed mode with the video still playing.
I of course then go into setting, set it back to full screen and then start the video again, this time it will play as expected in full screen.
I have attached the logs, but nothing jumped out to me about why this would be happening. Especially why it would happen on "first run" but not from there on out until the next session.
Any ideas on what to test?
Edit: Attached log file didn't seem to work, Pastebin of log file here