Might mean you have a mesh enabled AP that is intermittently unable to connect
AP is broadcasting an SSID of "island"
iWhat is an "Island SSID"?
When mesh AP looses connectivity with its uplink AP or Gateway
The Island SSID is known as the Mesh Recovery SSID which assists in recovering isolated Mesh APs in the event that they lose connection to their uplink AP. In order to recover, the Gateway should be defined in the AP's as described below.
Zone Director-controlled APs in a Layer 2 topology may enable the Mesh Recovery SSID while still connected to ZoneDirector if they are unable to contact the gateway, or the default gateway is not defined.
You can change and test it by going into ZD GUI --> Configure --> Access Points.
Click on Edit under Actions and enter the Gateway manually for that AP.
Once the Gateway is specified and saved, make sure to reboot the AP.