I purchased a used M12 and I can't figure out why the Ch 2 throttle neutral position is offset. I'm having difficulty calibrating my Castle ESC neutral position and I think it is because of the tx nuetral throttle position. Trims are centered, subtrims at 0, and EPAs at 100%. Please advise. Here are some pics:

check your trigger setup if it is set at 50/50 or 70/30. Some ESCs won't calibrate with 70/30 so set it to 50/50 then try again

Check sub trim.
Also try calibrate your transmitter.

Guys thanks for the tips. The final fix was even more bone headed than I thought it was going to be. I didn't have the ESC lead in the throttle slot on the RX. Doh

Got you, the throttle lead goes in after the servo lead.

I'm a moron. I've been in the hobby for 25 years and still missing things lol