Need help....Jake break spiking to 2000rpm from 1300 rpm when turning off

So I wanted the jake break to come on earlier. The dealer changed the parameter to 25 mph from 35 mph on insite. Now when I tap the brake it Jake's down to mid eighth gear, turns off and spikes to 2000 rpm. Rpms are supposed to be limited to 1800 rpm on this 2019 kenworth t680 with endurandt 12 speed. Dealer is puzzled and anyone I call doesn't know. Tried 15mph too for a parameter and same thing happened. If I start the braking by tapping the brake, and take my foot off it Jake's all the way down to half way through 8 and does this. Same thing happens if my foot stays on the break. Does anybody have something I could try besides going back to 35mph starting point. Have called insite, cummins, and kenworth with no luck.

 

Lots of stop and go back roads stuff so need the extra braking. Yes the transmission seems to be acting the same other than the current problem. So I think its the transmission...I caught it briefly flashing a 2 gear drop and then went back to the higher gear. Insight or cummins told me kenworth has an rpm parameter in the new trucks which will probably take care of this for the auto transmissions. I think you have to have the mph jake shut off parameter just right so it brings the rpm for my eighth gear all the way down just before it wants to jake 7th gear. Mainly happens when unloaded and stopping a little quicker than normal. Don't know if there is a parameter in the transmission to help this, but am happy with how the transmission acts otherwise. It did not do this when jake cut off was at 35, but it did bring ninth gear to a lower rpm before shut off.

 

The jake brake on this x15 is really good. Definitely stronger than the isx was.