I have an Elasticsearch cluster with Kibana installed on one of the nodes. We have a beta and a prod cluster which are generally very similar, however one of them has been having a strange Kibana issue. Normally, and on the working cluster, when you go to access Kibana you get the little login UI, however on the broken one it gives a login browser pop-up. Logging in works, but the Kibana UI is severly restricted. Going to the dev tools console, all commands work as if you are the user you are logged in as - it just seems like Kibana doesn't recognize that. Attached is a screenshot showing the missing menus (and also the little login bubble in the top right is missing).
I tried removing and recreating the Kibana node, as well as changing the credentials in the kibana settings yml. The logs are showing nothing out of the ordinary, and the clusters are otherwise running perfectly. We're also not sure what might have caused the issue - there's no major changes we've made recently that we can think of.
Both clusters are running version 7.4.2.