Reddit mentions of Valspar 1420 Color Changing Latex Ceiling Paint, 1-Gallon

I'm seeing the answer of it being mold and I don't know enough to rule that out, but I do want to bring up another possibility.

My first reaction to this was that it could be Valspar's color changing ceiling paint getting sort of "reactivated" by exposure to moisture. I've painted some bedroom ceilings with it recently. I went to clean a scuff off with a wet rag and thought the ceiling looked a little purple again after it got wet. I generally like the paint, but it may be an issue if used directly above a shower. I know you said it's pink, but it doesn't look too far off from the color of that paint.

I found this customer review about the paint "reactivating" when used above a shower. I also found a similar review on Amazon. Does it look like the previous owner recently painted some of the rooms in the house?

Edit: the more I look at this, the more confident I am that it's the paint.