ECM - intermittent reprogram required accelerator, throttle, idle air

[gemman69]

I have a 2005 Xterra that threw codes P1122, P1126, P0507, C1131, C1163. I replaced the throttle body, had ECM reconditioned, and I did the 3 relearns (Accelerator Pedal Released Position, Throttle Valve Closed position, Idle Air Volume Learning). Car ran fine. Restarted it a few times running errands. Ran fine. Replaced the battery. After battery change had to do the 3 relearns again. Ran fine. Start stop ran more errands. Without OBD2 code check yielded 4-0's. Sat over night. Ran fine 2 x on a round trip. Sat for few hours, ran in limp mode - reprogrammed again and it ran fine and restarted a few times.

Now, I have an intermittent problem. Why does the relearn get lost? What needs fixed?

[gemman69]

Did it again this evening, and I am now flashing 1122 & 1126. Same codes where this all started out. I relearned and it ran fine after that, at least for a while.

Ideas?