Zigbee light switch receives but doesn't send data

I have some Zigbee smart light switches, which have worked fine for a couple of years. However, one has recently started playing up. It correctly responds to commands sent from HA to turn on and off, but HA often doesn’t see me manually turning the switch on and off. Any ideas what could cause this, or what to do about it? It is mains-powered, so not a low-battery issue.
I guess if no one has any better suggestions, I could try deleting the device from HA, rebooting and repairing it, then updating all the automations that refer to it. But I am hoping someone has a better idea.