Z-Wave polling not working

I’m using a C5 (I have a C7 ready to install, but waiting for a not-so-disruptive time to port over 120 devices), and the Z-Wave polling has not worked right for a long time. Simple automation, Button and Rule Machine rules that try to toggle the Z-Wave switches no longer work. Doesn’t matter if I have the polling app running or not. The status of the device never seems to update to ON in Hubitat, even if the light attached to the switch is clearly ON. They used to work fine. I notice that if I push the Poll button on the device info screen, I get an error. I’ve tried doing a Z-Wave repair as well. Any idea why this might be happening?