I was having issues and did what RUNTHEWELL did (remove devices, uninstall app, reinstall the app, add the hub and devices back).
Everything seems to be better than before. I had issues where 1 device wasn’t reporting its battery percent, the devices saying it wasn’t able to start manual watering even though it had started it, and even sometime not being able to star manual watering at all. All those issues have gone away. Hardest part was trying to remember how to reset each device so that it could be readded to the app.
I only have 1 hub and 3 devices, so it wasn’t too much effort.