The tag stellar-core currently has no tag wiki guidance.
With most tags, when clicking on "can you help us create it"...
...the tag editing screen appears.
If you try to go directly to the edit page - stellar-core is tag number 32 on the site so the URL https://stellar.stackexchange.com/edit-tag-wiki/32 should take you directly to the edit - instead you get a 404 error.
Trying other tags directly by number does work, without trying every single tag, I only see the error on this one.
Update: Given the answer, I've removed bug from this.