Fibaro FGS221 not polling

Hi folks
My long standing FGS221 was suddenly started failing polls. Nothing to do with the FW upgrade as it was doing it before.
Odd thing is it still works just fine. So it’ll get a command, switch state and Vera will report it’s on line. About Then after n minutes Vera will report it’s off line and there it will stay until it next gets a command.
06 04/21/19 10:27:54.223 Device_Variable::m_szValue_set device: 18 service: urn:micasaverde-com:serviceId:ZWaveNetwork1 variable: ConsecutivePollFails was: 682 now: 683 #hooks: 0 upnp: 0 skip: 0 v:(nil)/NONE duplicate:0 <0x76c36520>

Any ideas? Replace failed? Or has it actually probably failed?

Cheers

C