I stand corrected - our APs _do_ look for Internet connectivity. All APs will look to our cloud based AP Registrar (APR) to see if they belong on a Cloud controller, otherwise look locally for a nearby ZoneDirector, SmartZone or Unleashed network, and if not finding any of these and running our Solo/Standalone firmware image, they would present a Solo/Standalone WebUI. I'm researching other Internet targets that might be used to detect Internet connectivity, ie www.microsoft.com, and captive.apple.com I've heard before.
I was curious about your question yesterday so I did a little digging. This is what I found... Our controllers will ping the following sites to ensure we have internet connectivity. apple.com, Microsoft.com, Baidu.com and support.ruckuckuswireless.com. We will do this every 3 seconds if we determine there is no internet service. If we do detect the internet is available we change that polling to every 60 seconds.
So it looks like the AP was doing what it was designed to do. Hopefully you can breath a little easier now.