The query given on the 'Top Tags without a Wiki' post can be up to a week out of date. The Stack Exchange Data Explorer from which the query is run isn't updated in realtime:
Therefore, the best day to check and update the query is on Mondays. However, if you click on the tags in the query, it will take you to the Arqade page for that tag:
Which will show an updated wiki in realtime. This is how I check when adding new tags to the answer.
I doubt there's any malice here, just a simple misunderstanding. I've edited in a warning to the post in question, hopefully in future, situations like this one will not crop up as often.
