OK. That's a pretty lame subject line. I'll expand it a bit.

I wanted to check a Remote Desktop function so I issued a Lock on my desktop PC, fired up my laptop, got an RDP connection to my PC, did some tests, and issued a Disconnect. All went well, but I couldn't get back locally on my PC. No lock screen, just a blank screen. The PC was awake but was apparently not willing to use my monitor. I have no idea if it was aware of the keyboard or mouse.

I finally got back on Remote Desktop and issued Restart. Now all is well, but I'd like to know what went wrong. I looked in the Event Log and saw nothing terribly unusual, but I'm not sure I'd recognize the symptoms.

What do I do to deal with it if it happens again?

BTW, both the PC and laptop are Win 10 20H2, build 19042.928.