Asterisk 16.17 PJSIP endpoints with max_contacts > 1:
There are 3 registered endpoints for this extension. Asterisk is sending outbound OPTIONS (qualify is set on the AOR for 60 seconds) to both those 3 contacts, as well as expired contacts on a different IP address that no longer exist.
I believe this problem started because I have remove_existing set to no, and due to an IP address change, the devices could not reregister as they hit the max_contacts limit. I used a database deltree to remove the contacts to force a registration which worked, but somewhere along the line the old IP is still cached somewhere and an asterisk restart is not removing it.