On 3 of 5 ESXi hosts in our cluster, we have had a few occurrences where a vmnic will appear to remain online but all traffic across it ceases and the associated VMs go offline. ESXi is not recognizing the failure so the VMs stay on that vmnic and don't respond to packets until I pull that vmnic out of the vSwitch which initiates the failover. It is easy to see using esxtop when the alerts come in for a bunch of VMs that use only one vmnic in the vSwitch. Has anyone seen this before? We checked the switch, the ports do not have recent flaps or any errors.
Build: ESXi v5 build 702118
Server: HP DL380pG8, 4 port on-board NIC (Broadcom)
Switch: Juniper