I think you are probably right even tho I bought it and took it straight home. It was 115 degrees out that day and I wasn't wanting to be out in it any longer than necessary. I laid it flat in the back of my SUV, but the sun did come thru the windows and the heat was nearly unbearable. I didn't expect it to warp tho.
When I took it back the staff at JoAnn's said that people had lots of problems with them. I guess if they lose business due to lousy customer service and product maybe they will start listening to us. :x