Based on the AP reboot events you have mentioned, there could be many reasons for the issue to occur.
"AP lost SCG more than 7200 seconds" means there was no communication between the AP and vSZ. Or there could be packet drops between the AP and vSZ.
About the other events, we would need the AP support log to find the root cause.
I request you to please open a support case from the below link so that the support team can check on this.https://support.ruckuswireless.com/contact-us