Due to today's train deployment more than doubling the error rate seen in fatalmonitor[1], I have rolled-back group 1 wikis to wmf.11. I've submitted an UBN task T172320 [2] detailing the error, which appears to be fallout from issues in Wikibase first noticed two weeks ago.

I expect that this will be easily resolved once someone familiar with the issue has had a chance to look into it and the train should be back on track in time for tomorrow's deployment.

1. https://logstash.wikimedia.org/goto/5acde54fdb7b071b5723607c9f57eb9c 2. https://phabricator.wikimedia.org/T172320