Last month on the Cordele/Crisp County P25 system I heard LEO traffic apparently repeated from another system onto talkgroup 38608 which is not listed in the db. I was just passing through.
Could have been a patch with an adjacent county. Crisp received grant money for an interoperability solution, which was to connect other LE agencies. The surrounding counties are mostly VHF.
The patched radio sounded like it was digital since the IMBE codec doesn't take kindly to double encoding-decoding passes. I'm thinking it was either a GSP troop or an adjacent county like you say. I didn't hear enough to tell, plus I don't know that area all that well.
I looked at my recordings and have a blip for that talk group, as well as 38640. No clear owners but likely another LEA patch. I have family in the area - I can try to sort it out.