Warning Hot Brakes?

I have a Dodge Ram 6.7 with an e brake and a 2013 Rockwood fifth wheel. We were coming home from about 1200 miles of Colorado mountain driving this week. When I was coming through Denver on I-76 and applied the brakes my Prodigy 3 gave me a "Hot Brakes Warning". The funny thing is that I rarely used my trailer brakes. I stopped in Greeley for about an hour and then headed home, the first time I applied the brakes I got the warning again. I know the brakes were not hot. What could be the problem?

One side note, at one point before I started getting the warning I had the controller set on Power Boost 2, when I applied the brakes the trailer brakes felt like they were grabbing and releasing like I was pumping the brake pedal. This only happened the one time.

Thanks