Noticed that once you've upgraded to the Cozy Cabin IV on the Island rain will fall through the glass roof in the middle area. While the sides with the bed and the bench remain rain free. Since the middle part is covered with glass I would assume that there isn't meant to be any rain falling through the roof.

Date & Time: Noticed it on 27.05.2023
Frequency: Always
World name: N/A
Character name: N/A
Retainer name: N/A
NPC name: N/A
Monster name: N/A
Class/Level: N/A
Party or solo: N/A
In-game time: N/A
Area and coordinates: Unnamed Island ( x12.6 , y28.5 , z0.4 )
Housing:
Steps:
1. Upgrade the cabin on the Island to the Cozy Cabin IV
2. Enter(or be present) on the island when it rains
3. Proceed upstairs in the Cozy Cabin IV and become wet.