See Problems to create an index pattern
I got the same behaviour as the above issue.
You create an index pattern but when switching to Discovery , it's not there. Also in the "Index pattern" screen it's not visible.
After restarting the Kibana pod ( we are running docker images ) , the index pattern is visible. Sometimes multipke times, as you retried before.
Looks like Kibana gets out of sync with Elastic.
We had the issue with version 7.5.2, and now with 7.8.0 , it's still there
Could be that the issue only occurs, after the first start of ES and Kibana.