Ran a print with the Light off and all plexi glass walls up on the enclosure. Started at 93 degrees and got up to 97 almost midway through the print before stopping it. Problem was still there.

Then ran with the Light off plus front & rear plexi walls removed. It started at 90 degrees and stayed about 91 throughout the print. The problem is no longer there. Going to run another to try to duplicate that result.