Strange, even when I manually change it, back to camera standard, then hit the alt key and reset button (which changes to "set default") it will not work. I get the drop down box telling me that this I can either change it to adobe defaults or my custom setitngs. I am selecting my custom setting, but it doesn't change it for all the current D810 image.
Also, there used to be a profile Adobe standard didn't there, I notice that gone now. I also don't remember "camera flat" being an available profile in previous versions of LR, but I may have just missed it.
Paul