The fresh water tank on ours almost fell out. The front rail was ok but the back rail was too far back for some reason, so the tank was hanging by not much. I noticed the extra bulge in the underbelly, thank goodness.
The fresh water tank is made of flexible stuff for some reason to do with it being for potable water compared with the grey and black tanks with stiffer plastic. So the fresh water tank bulges down when full.
In our case, it was after warranty, so I removed the part of the underbelly there and was able to shim the back rail tighter forward using more washers on the bolts (one rail is welded, the other is bolted--in this case the back rail was the one bolted) No problem ever since. :)
The Komfort people said it was all Lippert's fault for not spacing the rails correctly on the frame they ordered for that trailer. My opinion was the Komfort people at the factory who installed the tanks must have noticed the rails were too far apart, but didn't say anything, just perched the tank there anyway. Whatever, it was after warranty. :)