Hey. Went camping and had a wet few days. No leaks but when we were folding up the pop outs all, some more than others, the matress was wet in the middle bottom. Very strange. Anyone experienced this or know why it might happen? It was the worse in the rear pop out.
I'll bet you had hot, humid weather and you kept it nice and cool inside. That humidity will condense into a liquid when the dew point is reached. You might try adding some type of insulation blanket under the mattress.
If the reverse was true, and it was cold outside, moisture from the body will also condense when it travels thru the mattress and reaches the cold surface. Either way, insulation will help.
If possible, a thicker mattress that has better insulating qualities, is also a help.
You might want to try a foam mattress topper and use it under or over the mattress, the extra thickness is extra insulation. If it doesn't do the job, at least it might add comfort. Another option is to put the mattress topper on top with a sheet of plastic under it to act as a vapor barrier, but that might move around and cause other issues.
Is there room to add an insulation blanket or rigid foam insulation on the outdoors side? If it is an option it is not ideal. If any moisture gets between the insulation and the board it will take a long time to dry.
I was going to get a couple memory foam mattresses so hopefully that will do the trick. I would have to make changes in the inside. This is the first time this has happened so I am hoping the strange weather is the main reason