Sorry that didn't work for you Jon.
Now I suggest you go into the Global Expert Setings (PGM-Func-F3) and start lowering the "RF SQ Fade" number from the default setting of 10 down to 9. Then 8. Keep lowering until the problem stops. You will not want to go below 1.
As I understand it, The P25 transmissions don't have the end-tone like the analog transmissions. (So changing the EndToneMot setting probably did nothing to help.) Now, if you change the "RF SQ Fade" number it does have an effect. For instance, try turning it up to 99. After a P25 transmission ends you'll notice how long the scanner hangs on the freq before returning to the CC. (But after an Analog transmission ends it will instantly return to the CC if the end-tone is detected correctly.) So if you lower the "RF SQ Fade" number, it shortens the delay after the P25 transmissions.
The possible problem with setting this too low, like 1 or 2, is that weak "picket-fencing" signals can cause the scanner to prematurely move on to another transmission... such as a weak Weather Radio signal then jumping to another Weather Radio station. Still, not a big issue if it means you can stop the annoying problem you're having. I keep mine at 3. You probably still want to go with the SuperTrack OFF but you could try it both ways. It may be that I had already lowered the "RF SQ Fade" number before trying the SuperTrack setting. Let me know if this works. If not, I would contact GRE directly.
I really hope that helps. After someone says "Here's the Fix" you really figure it's going to work. Sorry for the disappointment.