Failed. Kibana 7.13.1 migration from 7.13.0 failed.
Testing setup. Single node. Fleet policies with Elastic-Endpoint only. Agent log's set to enable on settings to upload.
When the Elastic instance went offline for updates all agents started to buffer again in memory "Filebeat". This forced all machines to become unresponsive within 10minutes of each other. Forcing a hard crash of all test machines.
This is now the 2nd critical failure that has taken client devices offline that has been a different root cause but same results. 7.13 upgrade from pervious 7.12.1 caused the drives to fill up now it's back to memory starvation.
If I run into more I'll add on to this post.