Hi
I had a look for data on this IGBT module, but like you couldn't find any.
The Tracker 1000 has a limited range of stimuli, unlike the ProTrack, and later Trackers.
So on low range shows a good "diode knee", but jumping up to the Mid range switches the device hard on so shows what appears as a short, or the Trackers 1000 big jump in voltage on the Mid range cannot show the difference between a low value resistor across a diode or MOSFET switching on.
Perhaps Curtis will confirm or correct my diagnosis!!