I've currently got West & East Simulcast running, so it's one of those two. (i'll make better note of it next time I hear it).
Im running in "ID Search" mode, so it's picking up all the TG's regardless if I have it programmed in.
I see on the Northwest Intercept Talkgroup info for SNohomish County, 45584 and 45616 indicate "digital" in the notes. So possibly this is grouped up with that..?
I'll update my post with better info next time I hear it.
Thanks for the reply.