It very well could be system related. Whenever I travel to UT to visit family, I pass through Sublette county, which uses P25 phase 2 and I rarely see UID's displayed on my 536HP, or even my Unication G5. Also, their radio traffic is patched into WyoLink, and UID's rarely show up while listening on that system. I have no issues receiving traffic though.
Are you starting to see active TG's, or is everything still in testing?