My computer announced "Your computer is being remotely controlled press the escape key to stop the connection."

First my screen went dark, then the announcement came over the Mac speaker.

I had used my M3 MBP to to Screen Sharing TWELVE HOURS before my new Mac Mini M4 manifested these behaviors.

It concerned me because my laptop had been closed all night. I thought my Mini had been hijacked.

There's another thread (Closed now) about this on the forum. The answer was that the computer being used to access my screen had the high network resolution setting engaged. Supposedly that makes the screen being shared go dark.

I get that, but why did my screen go dark and my Mini make the announcement 12 hours AFTER I'd stopped using Screen Sharing? Or, was somebody else trying to control my Mini? I did have the Mini Settings for Sharing Screen and files enabled.