2020 JLUR popping out of 4l

I took my 6 month old JLUR off road at a local park yesterday for a few hours and a couple of times it popped out of 4 low and the message on the dash said “FCW unavaialable in low range”.
Should I have been turning off the forward crash warning system? Is it possible this was some sort of coincidence? Any insight is appreciated.

Also....

I should have noted that my Rubicon is heavily modified. 2.5” AEV lift, 4:88 gears, 37” Nitto Ridge Grapplers.

Sounds like you weren’t fully engaged. Did it pop pretty quickly after switching in?