We are seeing a large quantity of orphan packet messages in our syslogs:

%APF-1-CHANGE_ORPHAN_PKT_IP: apf_foreignap.c:1285 Changing orphan packet IP address for station...

These messages come in sets of 4-5 where the mac address is the same and the IP address is cycling among several of our subnets and a private IP subnet or two. Has anyone else run into this? What is the explanation for this and how do we find the root cause?