<s>[INST] I'm having some problems with my bathroom. The drywall is soft and bubbly in a corner of my ceiling, and there's some water damage. I can't quite figure out why it's happening. Here are some things I've noticed:
* The roof is new, less than 5 years old
* My home has a bathroom in the attic
* The water damage is confined to the one area on the ceiling, with no other signs of damage elsewhere in the bathroom
* I've not noticed any leaks anywhere else in the bathroom

What are some possible causes?[/INST]