Just wanted to share my observations. I've owned the X-T2 since september 2016, and I've pretty much been having lockups since day one - always in CH or CL. The lockups would freeze the camera completely, sometimes with a white EVF/LCD, and the green/orange LED being constantly orange. The only way to get it out of the lockup would be to remove the batteries in the grip.
At first I was using third party batteries in the booster grip (but the original NP-W126S in camera). Then I read it might be a battery related problem, so I bought two more NP-W126S. Didn't fix anything...
Then I read it might be related to my Lexar 64GB 150MB/s UHS-II cards, so I bought two new Sandisk 64GB 300MB/s UHS-II cards. Didn't fix anything either...!
At this point it started to get pretty expensive...
Scanned through every thinkable menu option and tried switching off "compressed raw". Well, I've been pushing my X-T2 all day now, shooting about 300GB of photos at 11fps, WITHOUT any freezing!
This could be it. I'll continue to test this, and get back to you.