Kbooster Health Connect access randomly stops and starts

I've been running this a couple of weeks now, and I'm seriously frustrated. As the title says, I can see Kbooster regularly accessing HC, and then at some random point in time it stops doing so, and the widget values all reset to 0. I've tried all I can think of (clear cache, data, permissions, rebooting, stopping, ...), both of Kbooster and KWGT.

What actually triggers Kbooster? Is there any way to force a sync?