Just ran into this issue.
I have a pair of vampires with the paranoid trait, so they live in an underground house built under a greenhouse and cannot do 'practice standing' with their twins even though we have chairs that work fine in other households.
Also getting the underwater error if trying to do tummy time while holding the infant (works fine if they're on the floor).
There are no pools on this lot either, though I do use the natural well lot trait.
do you have platforms in the lot?
Yes my lot does have platforms. It has a platformed 1st level, and then the basement access is a ladder down from the platform to the basement.
