Spoilers for Kemono Friends 2 Episode 9!
The newest domestic dog friend from ep 9 of KF2 is a new friend according to @kemo_project on twitter (who I believe is an official source), but on the newest posts (post #3442583, post #3442589, and post #3442906), she's just tagged as dog_(kemono_friends), who is a different friend. I think a more accurate tagging would be "イエイヌ (雑種)" -> domestic_dog_(mixed_breed)_(kemono_friends), or something to that effect.
Is the difference enough for a new tag?