I am having the same issue after the last update. Any ETA from Samsung on a patch? More than likely they'll make us wait until the next software update. Brand new watch, so far I am starting to regret sending them my gear s3 Frontier.
Here it is November and I too am now having issues with the GW4. The heart rate monitor won't even connect to running apps (Strava and Adidas Running) on my phone. There are huge gaps in Samsung Health, too.
This started last week after an update. Factory reset did nothing to fix it.