Here it shows “hello-world-2” which is the post slug+number (because the “hello-world” is assigned to “hello” tag) instead of the tag value “bye”: http://i.imgur.com/4LQwEOo.png
And on the wp_termmeta table it saves the post-slug as meta_value instead of the post tag value: http://i.imgur.com/lEBngcx.png