Hi,
If you using an InstantAP-105 - and you disconnecting the modem(ETH cable) from it - the iAP unit will reboot itself and will try to find another virtual controller via 5GHZ (mesh).
It's a basic feature in the unit itself. (redundancy feature in order to keep the service up and running)
*After u soft boot the iAP-105 while it connected to the modem (ETH) so agian the unit acting as a working virtualAP -with a working ssid and a working configuration like u had before u disconnected your cable :)
have a lovely week.
Me