After treatment problem.

Ok, another day, another problem.
This 2016 Cascadia never gave me this problem before. Now, I think mainly when I drive in a mountains, well not really mountains, let say hills, where truck has to work a bit and downshift to 9th or even an 8th. It throws engine light on on a dash and NOX conversion code SPN 4364 fmi 1 and fmi 18. Sometimes even engine light with check engine light and def light flashing, that when it kills speed down to 55 mph and cuts power 25%. Doing parked Regen ether from the dash button or from DDL seems to fix the problem till the next time which could be right the next day. This truck use to work day after day, month after month without asking for parked Regen. This truck also don't idle - I have an APU.
I performed parked scr efficiency test which passed. Parked regeneration finishes without any errors too.
So, where should I be looking for a problem?

 

LOL. Obviously. How didn't I think of it?