Playing the game regularly, I suddenly see dupes starting to make many messes, when before it was maybe once every 50 cycles.
As you can see in this image, Catalina (and other dupes) have a full bladder but think it is broken.
The toilets are assigned to public and are filled with 5000g water and 0g polluted water, connected correctly to plumbing.
It started suddenly. Save file is attached.
EDIT: Removing the toilet and placing it again fixed it, but I'm not sure what caused it in the first place, so the bug report still stands.
I don't have steps to reproduce, as it started spontaneously.