This issue manifested for me, after the UConnect 18.45.01 flash. 2015 HC Charger.
Never did it, before.
I enable my custom setting by double tapping the SRT button. Since 18.45.01, I get the cannot change power setting error, if:
1. Under acceleration
2. During deceleration
Sitting still, at a light... no problem. No error message.
On the fly, as long as I maintain throttle position, it's cool. If there is any throttle change... error.
Also, I have found that if I am driving and want to switch to custom mode, I can let off the throttle and wait a couple of seconds, then double tap the SRT button... no error.
@fumanchu182... you see this error? What do your logs say?
Bob