We had not opened up our PUP for 9 months. We went on our first camping trip of the year two days ago and when we opened it up, there was a musty smell. Usually, the smell is more of a campfire smell and this was the first time it smelled different. I had some potholders in the drawer and they had that musty smell on them also and the smell seemed to be stronger when I opened the doors under the dinette and the sink. I don't know if it is because of not having it opened for so long or if the smell means there has been water somewhere. We didn't see any sign of anything being wet so I'm not sure if that is just a normal thing.