340 XI Launch Cylinder Missfire

Mods; Downpipe Tune Mhd+ stage 2+ 93 octane chargpipe xhp stage 3 trans tune TU hpfp. Whenever I launch the car the 2->3 shift I get a drivetrain malfunction which comes back as a missfire when I shut the car off turn it back on it goes away. 90% of the time it’s cylinder 1. Is it spark plug?

39,500 miles