The trick for Apple Health is to leave Connect Mobile open for another minute after the sync with your Garmin device finishes. You should be able to go in to Apple Health and see your info afterwards. If it's still not appearing, force close Apple Health, sync your Garmin device, and wait one minute again.
I tried but it doesn't seem to work. Anyway, what do you mean by "force close" Apple Health? I know just one way to close an app on iOS.
Same for me - I get an occasional day when everything works in real time but then it's back to the usual 24h delay.