I have noticed a mildew odor in my shower the first time I use it on trips.  It usually goes away after my first shower. It has a "SHUB" shower door.  It retracts into a holder.  Says it is mold & mildew free.  Has anyone else had this problem and what did you do to eliminate it?

I don't believe it is coming from the grey tank as I cover the shower drain with a flat stopper while not in use.

So I learned something new this season.

I learned that all the little plastic knobs for the water connections loosen up over time.

Especially the water lines going up to my shower handle.  Must be the road sway.

I had to take an access pannel off inside a closet and found each knob was almost a full turn to make tight.

Just an idea you might look into.