This also happens on non-existent articles.

Thanks for filing it. I'll have a look at it at some point. I imagine it is caused by not finding the article in the index to get the source data.

Change 156686 had a related patch set uploaded by Manybubbles:
Morelike improvements

https://gerrit.wikimedia.org/r/156686

This fixes the problem for redirects - they now resolve. Newly created pages that have not yet been indexed will still return no results. This state only lasts for something like a minute now. Elasticsearch "refreshes" every 30 seconds. The job queue has been picking up edits instantly lately. Too instantly.

Change 156686 merged by jenkins-bot:
Morelike improvements

https://gerrit.wikimedia.org/r/156686

swalling wrote:

Thanks for fixing this stuff Nik.