I have had the GFC500 for 800+ hrs so far, had it installed Feb 2019. It has never disconnected in turbulence.
Once it disconnected in a hold and the second time it disconnected during normal flight. Both times it would come back on be normal for weeks/months later. It gives a long line beeps when it does disconnect, about twice as long as normal when you disconnect. Then one day a couple months later it just would not turn on.
Took it over to the avionic shop and Scott looked at something in the diagnostics and it told him which servo had a fault. It took about a week to get another servo and they replaced while I waited. It was in the wing, so I guess that is the roll servo? It was right at 2 years old and was covered under warranty. I think they have a 2 year warranty?
Good luck with yours.