After seeing your video, I entered the project again and waited, waited, and the hiccups started to appear. The gap from the FPS at the hiccups increased and I found another thing interesting: while the editor is open (not running or simulating) if you click outside the editor in a way for it to lose the window focus (ie: you can click on Windows’ Toolbar in the bottom) and then click in the editor again, you will see that the FPS presents a large difference from what it was before. To see the regular FPS back, the only way is to run or simulate. Im rolling back the driver just as an experiment.
PS: I have rolled back 5 versions back and the still there, so one can really reproduce it. As soon you get the number, let us know, so we can vote on it for fix priority