we run a cluster on version 7.6.2 and discovered that the refresh as well as the auto refresh are not working if you select one host. Here is how you can retrace the error:
In Kibana open Metrics App --> click on a host --> select view metrics --> in the time chooser select "Last 15 minutes" (first time works) --> wait for some time and press the refresh button. That will not work.
I tried also to use the auto refresh which also doesn't work.
Tested with Firefox and Chrome.
With a full refresh of the page the newest data is loaded.