Look closer for trash buildup on the block faces. I haven't heard of a warped mold from heat in my 27 years of business. I even poured red hot zinc in my molds till the blocks melted a little on the sharp edges, but they didn't warp that I could measure. And I CAN measure! I did get one back just recently that had a piece of lead that was nearly invisable between the block faces, and the customer had closed it with a vise, (presumably). It was warped .008.
When bullets are dropped from the mold back into the pot, small droplets splash up and often stick to the block faces. Being the same color as aluminum you'll probably have to open the blocks so they lay flat and use a magnifier to see them. -- Only tight unlubed alignment pins, or dents from being struck by hard obiects at the block face joint, or trash on the faces, can hold an LBT mold open. They won't warp....... That little row of dots was the easy way to spell PERIOD!
