I have had a Vivoactive 4S for about 6 weeks now. I have noticed that my settings from Connect seem to work only sometimes, and the failures are silent. For instance I was trying to figure out why when I take a very vigorous bike ride, for hours right up a huge mountain, I only got 13 intensity minutes. In the Connect app I have intensity minutes set to HR zones, but when I checked on the watch itself it is set to "Auto" which is apparently pretty bogus. The other thing that never seems to sync is the "auto" step goal. I can set the goal to whatever I want but if I set it to "auto" the goal never changes.
I never had either of these issues with the dramatically cheaper Forerunner 35!