I have experienced this issue, however it reset on its own within seconds. I do have active logging on one second increment and looking at my logs, I don?t see any interruptions with the VP-X, voltage or over current faults. What makes you suspect the VP unit? It seems more likely to me that there is an issue with the ADHRS (I have a GSU 25).
I had not experienced this until I updated the G3X to v8.3. It?s happened twice since then, but I have no idea what?s causing it or how to repeat it.
This topic probably belongs in the avionics forum...