I am just wandering if you maybe picking up skip from another station.
I know that Rowan County has bad skip on their State Fire patch.
What I mean is when somebody is using State Fire it will come across the Salisbury 800 Mhz. patch.
Same thing happened years ago here in Concord. I was at the mall and had my 800 Mhz. it started talking and picking up a fire department down in South Carolina with the same PL.
Same might be happening with you, since Forsyth Fire is carrier squelch.
Like I said it could be skip, because it does it at a particular time of the day.
Plus I doubt many radio techs unless there is an emergency will work past the standard 5pm work day stopping point.
David