This is a new problem, probably a month or so. When I move a window from my main (Monitor 2) to my second (Monitor 1), the resolution basically is cut in half. The window is bigger, the fonts are bigger, etc. They are both 3840x2160.
Included screen shots of monitors with your Settings window just dragged from one to the other. Also included the troubleshooting file.

THANK YOU OWEN! One of the most polite and helpful boots to the head I have gotten in a while. I rebooted, disable DF, and went to the display settings. I scrolled down and lo and behold, scale and layout was set to 300% instead of 200. Issue solved.