Last night, right before going to bed, I noticed that my 4K monitor seemed to be awake despite my computer being asleep. Upon closer inspection, I realized one of my cats peed on it, pooling right on the button board, causing the permanent awakeness. A lovely token of their anger that I left town for a few days.
I cleaned up the initial mess then and there, but knew it would require more work. Today I took apart the monitor case and cleaned every single part with isopropyl. After several hours disassembling, scouring , and reassembling, I finally have it working like normal, sans piss aroma.
I also just got a new 1440p curved monitor to replace my old crappy 2nd screen, so I got that set up as well. Now I have an even nicer system than before, despite the pretty major annoyance involved.
Cats are vermin. Cuddly, purring vermin.