Hawkspur

Hi all, I have a 2021 Sierra 2500 Denali and a 30 foot travel trailer. I'm trying to get the trailer length indicator feature to work when the blinkers are turned on without success - the feature is supposed to display a red overlay on the side camera view. The side view works, but not the overlay. I have the trailer profile set up in the trailering app with the correct dimensions and other trailering features have worked. Anyone have any ideas? The maximum length listed in 2021 trailering guide for the feature is 32 feet.