Spotted today while browsing the logs for something else, we have info messages on the "authentication" channel that say: "Account autocreation denied for CirrusSearch Streaming Updater by ClosedWikiProvider".
https://logstash.wikimedia.org/goto/23f85f00c7b9426ba607959076d3aab2
They stopped after we disabled NetworkSession on public wikis in T373826, but you mentioned that you want to re-enable it, so this will probably need to be resolved.
I'm not sure what the consequences of this problem would be, but it could be something like T373778? If it's not important, feel free to just close the task though.
