I take it you've observed this from a monitoring platform of some sort? I don't imagine you're sitting there with a constant ping running from a PC?!?! :smileywink:
10 minutes sounds more ARP related rather than an IAP reboot. Although granted normally 15 minutes is standard for this...
Can you validate it's not rebooted?
If it hasn't rebooted, it could be loads of things.
I guess you've checked wired and switch port errors to the AP etc?
With a view to "divide and conquer", your best option might be to get another IAP to site (with no radio config enabled), maybe on a different VLAN. See if that behaves the same? Is that practical?