Hi @alexus,
It sounds like you might be experiencing the same problem that another user reported. His solution was to put a proxy in between Kibana and Elasticsearch, but an easier solution for you might be to set the elasticsearch.healthcheck.delay property to a higher value (see linked issue).
If this is in fact what you are experiencing, then I recommend voting for https://github.com/elastic/kibana/issues/14163, which solves the underlying problem.