Hi Mark,
thanks for your input; you not seeing problems on your systems is an indicator of what the December 2016 updates did.
I say this because before those updates I had seen many postings on the forum about this issue, I even responded a number of times with replies such as yours, “I run the program on two Windows machines and I have never seen this issue”.
It is as if the program was fixed for one group of people and those fixes gave people like myself the issue.
As for trying different things, I have tried them all because I loved Fusion 360, I remember you being around during the time of those updates. I am not sure if you can remember them but the biggest issue for most was they broke the move tool and numerous other things. They then rushed out 3 or 4 updates and nothing has ever been the same.
I have now tried to run the program on 3 completely new machines and the behaviour is the same on all 3.
I believe this is not the only issue those updates have caused; the program is unstable and has been ever since those updates. This can be seen by all the good engineers who no longer frequent this forum and by all the issues reported every day.
I am not sure if you have downloaded the file I attached above but for a modelling system that has had tens of millions of dollars spent on it to do that, is ridicules.
If a projects foundation is weak the whole project will either collapse or give you hell until you collapse. I believe that to be the case with Fusion 360, December 2016 updates destroyed the stability of Fusion 360.
To check if you can reproduce my problem you would have to stay offline for a couple of days, I am not sure if you work offline to that extent?