Intermittent exhaust brake

Ok so a couple things I’ve noticed:
The exhaust brake will not always come on under 60° (Going by outside air temp on overhead console)
The exhaust brake does not always come on immediately after letting off fuel (in any gear)
Around 1600 the brake cuts out and back in at 1500

Anyone else experience these situations?
I read somewhere about an AX update? No idea what that even means. Maybe if someone can elaborate I can figure something out.

My setup is a bd exhaust brake hooked to factory switch with a Hardway performance csp-5 tune.
S467 and all necessities to run it (dual cp3’s, injector tips, studs, etc)
Manual trans
2007.5
Tune is from 2013

All advice/suggestions/tips are appreciated thanks