Interesting, I was able to use the same driver with the QSI dongle for either JMRI or QSI software.
Also, note that it worked better out of the loco, so you might check your track pickup wiring. Is there any possibility you still have something connected across the rails. Next time you remove the decoder, you might check the resistance across the rails with the loco on the rails…
I had a friend that went nuts using graphite for lubrication, and did not clean the journals on the wheels first… the old oil caked up the graphite and that caked graphite created a low level short between axle and wheel (across insulator)… so strange stuff can happen… happened to me on an Aristo E8 where there were little lights over the trucks connected to the track pickups in a place that was not obvious.
Anyway, the PTB-100 seems to help, but be aware you may be covering up some wiring issues. Mine is still in it’s bag for years and like I said, I have a LOT of QSI Titans.
Greg