@gmp
Not sure what "internet connectivity" means exactly vs. specific OS or application s/w updates but there was a recent Win10 Pro update on this system (more than a couple days ago) before I decided to try release 2016.12 two days ago. The simple test project passed the test and so far the money projects are all opening/running with no issues, with the GUI appearing to be much "snappier" (responsive).
Please note this is -without- updating to the "early releases" announced for the two CW VSTs (no time for beta testing at the moment.) Of course, that will be the first thing I try if I run into problems again.
This is pure unqualified speculation on my part, but perhaps in your case, given the "timing issue" noted by the CW devs, there is some "timing issue" as a result of running the network drivers on your PC. By disconnecting, you may have changed the state just enough to make a difference.
Since I can't claim any specific action on my part to restore performance other than what was mentioned in my update, I'm going with the elves.
Happier holidays.