When I work in the develop module in Lightroom CC it tries to refresh everytime I make an adjustment. Sometimes it undoes what i just adjusted. Any ideas what may be wrong? I'm on a 27 inch IMAC. I have the lasted update 10.10 something. May be just a bug that they haven't worked out yet.
I don't have an answer, but I have had that happen to me a couple of times as well since I upgraded to LR cc 2015 (LR6).
In the preferences dialog, in the performance tab, if the "use GPU" is turned on try turning it off.
Lots of reported problems with the video cards, mostly ATI cards.