I suddenly have the bug on my iMac. Usually when I log in the balance is off so I created a script to set it back (first to the far left, then to the far right and then center; if I don't do it like this it won't work) and turned the script into a program with Automator so I can add it to my Login items. Took a few reboots to get the timing in my script right but now it works. I'll wait for the 10.10.2 update and see if this fixes the issue.