In SEPM under policies, is Host Integrity listed?
If so select that. Do any Host Integrity policies have a location use count greater than zero?
If so, find the policy with a Host Integrity Policy and withdraw the host integrity policy.
If you dont have Host Integrity listed, first try running the SEPM install again. I'm not sure that will work. (didn't think to try it). In my case support sent me a trial copy of snac12.1exe. It has sepm, sncac and the dhcp plugin. When I ran the sepm from that package it upgraded my sepm adding the nac pieces. Only after I did that did I see the Host Integrity policies.
After I withdrew the host integrity policies, everything is back to normal. No nac licensing errors, no nac listing in the gui. The SNAC service is now disabled. I'll have to test if the SNAC service is installed at all on a new system or if it goes away after reboot. Pretty sure I'll need to rebuild my install packages since they would have the old host integrity phantom policy in them.
hope that helps.