Update: When I spoke to the dealer, they said we should just leave the cover off more (like all day) as it was so well insulated it was trapping heat. I can't say I loved this suggestion. Well, I left it off, overnight the water cooled down to 91 degrees, and then miraculously it healed itself.
We have the temp set at 99. We leave the cover on when not in use. It is staying at 99 degrees (despite the fact that the outside temp has creeped up the last few days to 90 degrees, hotter than it was when the tub was self-heating to 103). Weird.
To make up for the fact that it is working as hoped (temperature wise), the waterfall isn't always working. Another call to the dealer is on the way! I still love to soak in this tub but it sure would be nice if it would work as it's supposed to on a consistent basis!!