Oh, shoot... I just figured it out...
What I'm seeing is the truncation of the second-to-last line on the terminal... with a bit more traffic on the system than there was late last night, I'm seeing:
TDMA Slot
TDMA Slo
TDMA Sl
With the default font, 'l' looks a lot like '1' and I was interpreting 'Sl' as "Slot 1" 8*P
Sorry for the confusion...
In my defense, the particular talkgroup that caught my eye was a bit unique to begin with - it had started out as a patch to an analog conventional repeater and was only ever FDMA on the trunk. Recently, it's been switched over to TDMA full-time, and I got it in my head that the 'o' might have been a flag for something I wasn't familiar with.
Thanks again for all the hard work that goes into op25!