From all the posts I have read about this issue, it would seem that Fuji has no idea what is causing it! But obviously many X-T2 users have not (so far) experienced this.The reasons for lock up seem very varied, wierd!
Look forward to seeing more of your wonderful photographs, now that your baby is back home! But FW 2.10 is still the latest at the Fuji website. Maybe they are about to release 2.11...Good news, today my repaired X-T2 returned to my sweaty little hands.
According to the document enclosed the Main PWB was replaced as was the top plate. Also the camera firmware was updated to 2.11, so just maybe part of the problem was firmware related?
All this cost me not a penny due to the camera being just in the warranty period which runs out in September, well done Fuji. It now looks like a new camera as the top plate replacement also meant that the dials which had a dodgy numeral paint have obviously replaced when the top plate was changed. It's nice to have it back, and as a bonus it came with a 126 battery installed which I had not sent back with it. I can stop biting my fingernails now.
Once again I can go back to being a happy chappie!