Just set up a VPC peer-link between two 7010 switches. The peer-link is a port-channel of two 10Gb connections. On both sides I'm seeing this in the log:
2010 Jan 5 04:27:34 CRMCN7K-1 %ARP-2-DUP_SRC_IP: arp  Source address of packet received from 0024.f716.b341 on Vlan401(port-channel10) is duplicate of local, 10.180.0.17
and on the other
2010 Jan 5 04:23:39 CRMCN7K-2 %ARP-2-DUP_SRC_IP: arp  Source address of packet received from 0024.f71f.a7c1 on Vlan401(port-channel10) is duplicate of local, 10.180.0.18
VLAN 401 is the only VLAN on them right now with a Layer 3 address. What am I missing? Everything looks correct. Port-Channel10 is up and running fine..or so it seems.