Wrinkling around windows

ayjvee

Hi, I've just bought my first motorhome. (2001 Elddis Sunseeker 35) and at the time of viewing I failed to notice random 'wrinkling' of the vynil covering inside the van.  All of this occurs at odd points directly next tol the windows (sides and bottoms
mainly).  It's as though the wall covering has been 'gathered up' or perhaps worked out and away from underneath the window surrounds.  I've tested them all with a moisture meter and, as with the rest of the interior, they give a zero reading.  I wonder if
anyone else has come across this?  If so, what might have caused it and perhaps, what can be done to cure it?

Many thanks,