Some tags are not loading

I have a tag ‘a(接頭辞:~の方へ)’ with 80 posts.

Screenshot 2020-04-15 at 12.20.15 PM

when I click on this tag to view all the posts associated with it, it shows a 404 page not found.

Any idea why this happens?

Note: The query works fine but still the tag is not loaded.