I had the exact same issue and can offer some insight. In short, I believe it is an issue with a recent update to the SmartThings Classic app, but that it will work perfectly with the new SmartThings app.
Here’s a detailed version: I have the genuine Fortrezz version of the shutoff valve. It had functioned flawlessly for over 2 years. Then around early July 2018 it started misbehaving, exactly as you describe.
The “Recently” tab shows the correct state of the device, but the “Right Now” tab does not. I tried re-pairing the device and rebuilding the network. I also moved the hub right next to the valve. It would work briefly after re-pairing, say for 10 minutes at most, then fail. Most commonly, once closed it would show the valve as open and would not respond to commands, but its behavior was inconsistent, in that it invariably would fail to respond to commands from the app in either the open or closed position. Manually (by pressing the buttons), it operated correctly. I had been using the classic app. I don’t even know what Webcore is, so obviously I was not using it. However, I had the valve connected to several smart apps including leak detectors, presence detectors, and the Fortrezz flow detector.
The device is installed in a vacation home 1,000 miles away, so I could only work on it intermittently. It was very frustrating.
I had decided that the physical device itself must have gone bad and resigned myself to replacing it. Surprisingly, when I checked Amazon, I saw that the WaterCop, which looks nearly identical (except for the built in water sensor) was a small fraction of the cost of the Fortrezz, so I ordered two of them (one with and one without the brass valve, as backups).
Since I will not be at the vacation home for some time, when the new WaterCop valves arrived, I actually built a test network at my present remote location, setting up a new Hub (v2), new SmartThings account, and adding each of the two new valves into the network one-by-one, as the only device. (The Fortrezz device at the vacation house is installed in a crawl space, so the test setup was a lot more convenient.)
The two new WaterCops behaved exactly the same as the Fortrezz using the classic app (either iPhone or Android version). While I had not yet received an invitation to upgrade to the new app, just for kicks, I installed the Android version of the new app. Lo and behold, on my test account, it automatically detected both new WaterCop valves and they both work just fine now.
So, I guess what I’ll need to do is migrate everything over to the new app. I will only do this when I am at the vacation home because, right now, the valve is stuck in the open position and water is needed there for the irrigation system. I don’t wish to risk having the valve getting stuck in the closed position (although I risk the possibility of a leak developing with no way to turn off the water).
Long story in short: given that the Fortrezz valve had worked perfectly for two years, my valve started failing around the same time as yours and that the two new WaterCop valves I tested work fine with the new app but fail with the classic app (even though it logs the history correctly), I conclude that there is a fresh bug in the classic app.
Hope this helps.