I have my 'Digital Gold' Art Panel mounted under an AC vent, about three feet away. For whatever reason (temperature changes?) after a day the panel started to bow outward at the right and left edge. I could push down and straighten out but as soon as pressure was removed the warping came back. The front of the panel is perfect as my previous photo showed. Frank offered to replace the panel at no charge but I really did not want to part with it.
Also, there was the concern that being mounted right under an AC vent a replacement might have the same problem.
Over time the warping became a little worse so I decided to take care of it myself by stiffening with three pieces of 3/8" hardwood millwork applied with Gorilla one inch double sided mounting tape as shown:
The panel is perfectly flat now and the mods do not interfere with mounting. Cost was $16 for the millwork/Gorilla tape and took less than thirty minutes. I wanted to present this easy fix in case some one else has the same problem.