This has been mentioned before, but it's still not working right.
What's happening is if I use the hydration widget on the watch to track hydration WITHOUT BEING CONNECTED TO MY PHONE it will not sync later when I do connect the phone.
To make the hydration sync, after I connect to the phone I have to go into Hydration and click + or -. It's the only way to sync. Running just the sync from the app or the watch will not do it. The value has to be changed.
In the few days I've had the VA4, hydration appears to be the only data that will not "sync up" when you connect the phone. All other data seems to sync fine.