The APs are designed to use their CPU, so high CPU isn't necessarily a problem. They shouldn't be constantly at 100% however, so we need to narrow down the cause. You've stated you aren't using the services that mostly commonly spike the CPU, so we've ruled that out. In your description you mentioned "some cryptic looking services", could you tell me what those were?
A packet capture would also help us get a better look at your traffic to make sure we aren't getting flooded, which is another cause of CPU spiking. Could you run a remote packet capture on the AP you see with 100% CPU? This guide will walk you through how to run a packet capture in HiveManager: https://thehivecommunity.aerohive.com/s/article/Packet-Capture-in-NG
Finally, could you share the results of "Show system process state" and "show cup detail"? If you'd rather send this to me directly, my email is communityhelp@aerohive.com.
