We had a VMware ESXi host start to display this following a networking instability issue. The host was checked and it did indeed have network redundancy, so this message was not correct, and appeared to be stuck warning about a condition that did not exist.
Resolution is given in: https://kb.vmware.com/s/article/2008602, and in our case just right-clicking the host and selecting Reconfigure HA was all that was needed to clear the fault.