Seriously? A single space made your loop run forever? That's wild, but it happens all the time with user input. Always cleaning data first is the way to go.

My grandma’s 1950s aspic mold still haunts my dreams, honestly.

Two days between coats is probably too short for lightweight mud to fully dry and shrink. Let it cure for at least a week next time, and make sure you're embedding the tape well with enough mud.