Usually it's NOT the paint that's "checking". It's the surface of the fiberglass coming loose.
Several RV manufacturers had problems due to using the same panel manufacturer. Not cheap to fix, on our rig it's some $18,000 to replace and repaint the whole sidewall.
2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft, HWH Active Air
Charter Good Sam Lifetime Member, FMCA,
RV'ing since 1957, NRA Benefactor Life, towing '21 Jeep JLU Rubicon Ecodiesel