AC1200 (model C6220) Does this device log IP address conflicts?

> [...] I suspect there is a periodic IP address conflict [...]

   Any evidence for that?  ("periodic" or "occasional"?)

> [...] it might log a detected IP address conflict. [...]

   I'd expect to find evidence in the log of the DHCP server granting an
address to a client device.  I wouldn't bet that the router would notice
a conflict, let alone record it in its log.

   In my experience, the usual cause of an address conflict is the
presence of multiple DHCP servers on the LAN.  Less frequently, a user
will assign a static address (not a reserved dynamic address) to some
device, but leave that address in the DHCP pool, so that the DHCP server
can grant it to some other device.