If you have built a chest inside of the house after purchasing it, and then it somehow catches fire, all the items inside of it won't drop when it's done burning. The same seems to apply to shelves in your house, but I'm not sure if this happens in stores too.
Steps to Reproduce
Let a shelf or chest inside the Slanty Shanty burn while it has items in it.
Let a shelf or chest inside the Slanty Shanty burn while it has items in it.