Is this the first signs of damp?

cricketscotty

I have a 2007 Avondale Argente 2 birth and whilst away last week noticed on the inside near to the front of the van above the vertical cushions on the side wall an area of approximately 4-5 square inches of what looks as if there is sharpe sand under the
wall covering. It is hard to the touch and bumpy but does not appear to be on any other internal walls. There is no evidence of water penetration when viewed from the outside and there are no jointsor seams nearby. Anybody got any ideas?