Puddle caught between floor and ceiling, can't mop it?

So there's a puddle on the floor of one of my upstairs bathrooms, but when directed to mop it my Sim goes to the floor underneath it and then waves their hands and says they can't get to it. I've tried all the fixes on Google - building a wall through it, etc - but the puddle is stuck there. testingcheats on + shift clicking doesn't bring up an option to destroy it, only to reset it, which does nothing. Any ideas?

edit - I just ended up deleting the whole room underneath and rebuilding it, that seems to have worked. Weird that a puddle can get stuck like that, between floors. Anyone else seen this?