I had a similar problem with a Fibraro water sensor.
Homed has lost the device, but the device itself has the state “connected”.
I got it fixed with unpairing.
Go to setting in the Homey app.
Go to Z-Wave
Select “remove a Z-Wave device”
Then set the extender into pairing mode.
This should unpair the extender.
After that you should be able to add the extender again to Homey.
