Probably simulcast issue. 996 scanners are not good at decoding simulcast transmissions, but the Unication is really good. You are probably receiving signal, but the scanner is having difficulty decoding that signal into something intelligent.
When I visit family in the twin cities, here is how my scanners are programmed (my emphasis is on fire "stuff"):
System - MN ARMER
Department 1 - Hennepin East (site)
Department 2 - Hennepin West (site)
Department 3 - Minneapolis N/S (site)
Department 4 - Minneapolis City Center (site)
Department 5 - Ramsey (site)
Department 6 - Anoka (site)
Department 7 - Dakota (site)
Department 8 - All Fire Talkgroups combined into one
I'm using SDS scanners, so their term is "Department" for both sites and Groups. You would have to adjust accordingly for the 996s. Also I'd probably use just the primary and alternate control channels for each site, rather than all the frequencies. You are limited in memory more so than the SDS models.
Without going into a complicated explanation, the ARMER system is designed so that sites cover a given area, modest in size. For example, the Ramsey site would cover just Ramsey and its signal would not be received around Lake Calhoun or whatever its called now. (If units from St. Paul go into Minneapolis, they are allowed to use the Minneapolis site, like cell tower roaming.)
All that said, the ARMER system is as complex as they come and the metro area is the most complicated of the whole state. Once you get the hang of that, you'll be able to deal with anything that comes your way.