Not to stir the pot, but I have been having issues with my trans with the Xtreme X as well...
Local shop went through the trans 3 times under warranty after the first build. All hard parts including clutches and steels have been fine, they usually just replace the electronics and all is good for 3-6k miles. The last time, they started with a fresh core and built up from there thinking there could have been a small crack in the valve body or something causing the issues. I had thought it could be tuning, but hadn't tried anything since my research found nothing. Now I am out of warranty for my built trans and it has acted up again. I am going to try my old tunes that were always rock solid.
My issues have always been while driving 20 miles + on the highway at 60mph+. The T/H light would flash and a code would show for a converter issue. Basically the converter wouldn't lock in 5th. After a while, it would slip into neutral for a split second, back into gear and would basically lose 5th gear and be stuck cruising at 55 turning 3000k rpms. If I shut the truck off and restarted, all would be fine for another 20 miles, then the process would start over. If I completely reflash the tune, it is fine for more like 1000 miles before I have issues again.
I am going to start by running stock for a while and see if it does it, then slowly add tunes up to my street file. If all is clean, then I am pointing to the Xtreme X...