タグは全員が使用可能ですが、タグの使用はスタッフのみ限定されます

Yes, I can repro this on try. Repro steps above are correct:

  1. Create a tag group with some tags.
  2. Edit the tag group and set “Tags are visible only to staff”.
  3. Edit it again and set “Tags can be used by everyone”.

Non staff users cannot see the tags in this group at /tags, and attempts to create topics with the tags fails with The tag "tag_name" may only be applied by staff.

「いいね!」 4