I upgraded my Note 3 to Lollipop maybe a week ago. Until now, I haven't noticed any problems, but today a big one came up. I was doing some reading, and the notification that I was getting a call came up, I told it to answer, and it came to the phone screen. I swiped to answer, and... nothing. I kept swiping the green button in every way, but it wouldn't answer. I'm very glad I set up my voicemail, because the call was about a pair of interviews.
I went through the troubleshooter assistant, and now it doesn't show that a call is coming in at all.
Now, the calls are answering. But this really needs to get fixed.