Server Version#: Version 1.28.1.6104
Player Version#: (Windows) Version 1.68.2.3746-7601b337
With a multi-monitor setup at different resolutions, and one monitor at a 125% scale set in Windows itself, the plex for windows application starts full screen at the wrong (too large) resolution, so only a part of the screen is visible.
The only fix i found is to exit full screen, drag the window over to the monitor I have set at 125% scale, which automatically resizes the Plex window to the correct resolution, then drag it back to my main monitor and go back to full screen. This happens on every start of the app.