The local system you entered was Dare County Public Safety Project 25 Phase I, yes? 

Earlier this year, I was visiting Pawleys Island, SC in Georgetown County.  Using my 436HP with GPS, I would get the Palmetto 800 P-25 Phase I system with plenty of SCHP traffic and other traffic but no Georgetown County Talkgroup user traffic. 

I entered a Pawleys Island zip code, again plenty of SCHP traffic, but no luck for Georgetown County TG's

I had programed my 396XT with Georgetown County Conventional freqs but had not programed the Palmetto 800 System since the 436HP would do that via GPS/Zip Code. 

I manually programed the Palmetto 800 System with SCHP and Georgetown County TG's in my 396XL and began getting traffic on the Georgetown Local TG's.  I then did the same, manually programmed my 436HP and began to receive Georgetown County TG's.

Programing manually worked fine.  Using the GPS and/or Zip Code function, I wasn't receiving Georgetown County TG's.

Manually programing both systems might have been the solution, it worked for me in Pawleys Island, SC.