I am not sure if a support ticket is called PMR in the Apple world, but I opened my first one this evening.
I experienced some trouble on the iMac since I installed macOS Sierra 10.12.1 update about a week ago.
This is how the problem occurs:
At least once a day my desktop completely freezes while surfing with Safari. Facebook is my homepage and it rarely occurs that the desktop completely freezes when e.g. a message popup is displayed or during scrolling through other pages. I can move the mouse cursor but can’t click or change windows etc. The dock is also not available.
I am really glad I found this thread in the Apple support forum: https://discussions.apple.com/thread/7687562?start=0&tstart=0
The users report similar issues. In addition I already had a random restart during the machine was in suspend mode after about 5 minutes. This was reported by one user, too. I just can guess what the problem might be, so I decided to contact the Apple support directly via Twitter. I am exchanging messages during the evening for some hours now and I really hope that this will be addressed very soon.
As the Twitter way isn’t resulting in a „real“ ticket I don’t take this too seriously. I also don’t have active maintenance on my apple devices so I am very happy and pleased that they are responding and interacting with me.
So stay tuned - if I have a solution or fix I’ll let you know.