Host list under the cluster node on the left hand is missing.

Hi,

One of our tester find the host list under the cluster node is missing,this will cause one critical problem to our plug-in.If we click the refresh button.The host list will show under the cluster again.(This issue will not occur in the vcenter 5.5 and 6.0)

Can you help to see this issue.

In the picture above,no host list under the "cluster" on the lsft hand,but in the "Related Object-host"  list,there actually exists a host(10.240.197.245),this is quite strange.