Major Description
A chicken/egg issue of the way the autoscaling SystemLogListener uses the .system collection to record event history is that in the case of a nodeLost event for the .system collection's leader, there is a window of time during leader election where trying to add the "Document" representing that nodeLost event to the .system collection can fail.
This isn't a silently failure: the SystemLogListener, acting the role of a Solr client, is informed that the "add" failed, but it doesn't/can't do much to deal with this situation other then to "log" (to the slf4j Logger) that it wasn't able to add the doc.
I'm not sure how much of a "real world" impact this has on users, but I noticed the issue while diagnosing a jenkins test failure and wanted to track it.