Zigbee device detached inexplicably but still functions

I have no idea why, but today the Z2M map shows that my Samsung Motion Sensor is somehow - detached - for lack of a better word, from the zigbee network.

It doesn’t seem to be causing any issue as such, as the device still triggers the hall light to switch on.

Can anyone help me reconnect it, does it need reconnecting, why has it disconnected, is it harmless?

Oddly, it just re-added itself at a later time… weirdo thing!