While providing the tags to this very question, I get 5 tag suggestions after typing "bug". When I click on "learn more", the info page of the respective tag opens in a new tab. This is good. Now, after typing "tag-sel" I only get 1 suggestion, namely "tag-selector". When I click "learn more", the tag "tag-selector" is selected and no info page is opened.
I've tested this for a few tags, and this buggy behaviour seems to appear whenever there's only 1 tag suggestion. (Test it yourself at the edit link for this very question!)