Found cabover rot!

Someone else suggested on another post to take a small drill and put a few test holes into the wood. If soft and rotted then problem, if hard and woody your good.

If good I would add some silicone or wood filler into pilot holes to seal up.

Had that in my old palomino. There was a leak in the roof, leading water to dribble down the inside walls and eventually pool in the cabinets and floor. It was a slow leak so things like heavy dew and light rain were enough to lead to constant moisture and long-term rot. The floor was sagging and soft, the walls developed bubbles and eventually the ceiling began to sink and cave in. I had purchased it dirt cheap, so I wound up giving it away to a guy looking for a project to occupy himself with. Sounds like you should be looking at the roof for any openings or bad seams.

It's in the cabover, no plumbing up there, I am worried that the cabover floor may have rot too.

Inside wall only leads me to believe a loose plumbing connection.