It’s a Topdon BT100. I got it on sale for $45.
Amazon.com: Car Battery Tester 12V Load Tester, TOPDON BT100 100-2000 CCA Automotive Alternator Tester Digital Auto Battery Analyzer Charging Cranking System Tester for Car Truck Motorcycle ATV SUV Boat Yacht: Automotive
My TB is clean, just did it recently.
I agree it probably has to do with learned data stored in the VRAM, but I think it shuts off first time as part of a test routine.
I’m surprised you said it’s never happened to you, what’s the longest you’ve gone with the battery disconnected?
I can see TB position sensor data on the ScanGauge, wonder what normal is.