Not a new thing. The crew will check and refresh/restock the lavatory at least every 30 mins. We're also required to keep it tidy to a certain extent. However, we simply don't have the facilities or equipment to clean up any significant or specific 'mess', shall we say. In the worst cases, the toilet will simply be locked off for the cleaners at the destination to deal with.
Some routes are known to be worse than others for this. I'd *always* recommend wearing shoes to the lavatory.