This morning I noticed all of my Inovelli Red series light switches still showing the system was armed when it should have been disarmed and when I walked into my bathroom the light didn't come on like it should have with motion nor did it turn on the other lights it should have for the morning after detecting me entering the bathroom after 7. I looked at the dashboard and the hub was disarmed and motion detection was working but none of the Z-Wave switches I tried worked so I shutdown the hub, unplugged it for about 10 minutes and plugged it back in. After it came back up everything was working again. This is only the second time Z-Wave has stopped functioning and the last time it was only the secure devices but this time it was the non secure devices (I didn't try the secure devices). I probably wouldn't have noticed the Z-Wave issue before leaving for work today which would likely have been noticed by my wife at some point without the switch notifications.
I would suspect that you have a run-away app or integration which is causing your hub to start to hang. Have you been able to look into what was happening at the time to see what might be causing this condition?
Like I said this has only happened twice in the last year so it's not something that is easy to track down and know that its been fixed. I got logs last time but they didn't show any issues and this morning I didn't have time since I wanted to fix it before leaving the house.