There's a few of reasons we would want to disable MAC Address Conflict detection on an IP address basis:
- The Conflict is discovered by a combination of Neighbor/ARP scan and pings from other routers and HSRP
- Proxy ARP issues?
- Known faulty hosts whose MAC changes, but cannot be fixed
- Troubleshooting situations where a static must be assigned while troubleshooting even within the DHCP range
Ideally, some sort of audit or reason should be logged for disabling the detection. Documentation on Conflicts could also be expanded to clarify why one should or should not disable Conflict detection.
