HostXYZ "currently has no management network redundancy"
But wait - thats not true, the vSwitch clearly has two active connections!
I tried reconfiguring the ordering of the nics in the teaming config, but the warning persisted.
Then I found KB1004700 which starts talking about ignoring/suppressing the warning (very bad practice to ignore alerts! for what should be obvious reasons).
But I kept reading and saw:
"Note: If the warning continues to appear, disable and re-enable VMware High Availability in the cluster."
So I disabled and enabled HA and this cleared the alert - no suppression of alerts needed!