" The VMs are of course moving sometimes with vMotion and possible this at some point confused some network device and caused the logs. If it just was on a single occation I would guess that you should not worry too much.""
Is there any other reason can be for host ips "flapping" other than you explained above ?
VMware KB: Physical Link Down with Loss of Redundancy
Note: These alarm can also be triggered if there is a limit placed on the the Broadcast traffic on the physical upstream switches. ESX/ESXi hosts rely on Broadcast Traffic and if there are limits set, it may cause flapping on the vmnic during vMotion
i verified everything with network team and could not find anything ?