I was having a few fits with GFX files about 2 weeks ago, and then with D810 and D850 files in LR. Then I noticed that the default profile for LR Classic CC has reverted back to "adobe standard" instead of "camera standard".
For me it's a big difference for both D850 and GFX files. Simple enough to fix, but not sure why LR has gone back to this. Issue came up with the D810 when it first came out also, and then in a later version LR went back to camera standard.
Paul Caldwell