What would then cause the warping?? Almost everywhere I've ever bought records have carefully stored them on their edges, in their paper sleeves, inside their original covers. Of course, more unconventional sources are more chancy, though dirt and scratches seem to be more of a problem than is warping.
I was, however, witness to a supreme warping of a treasured Little Richard LP, lent to my brother and subsequently left in the back window of his '56 Ford in summer heat. It looked like one of those wavy-edged seashells that one sometimes sees.
I've seen storage in the shrinkwrap cause warping of covers if the item was exposed to a damp environment for some time. It did not have any great effect on the wax, but I can't imagine it did any good.