[spoiler]LIAR! I just fought Feral Boars and I was double-teamed, NO DROP KICK.[/spoiler]
[SPOILER="Spoiler"]Did you hit one boar right as another noticed you? That is, it could be that the passive aggro of a boar triggered right when you decided to attack another boar.
From my experience, I have never been double-teamed unless I let the above situation occur. Keep in mind also that, while you're fighting a boar, a second one may "notice" you (a single exclamation mark), and upon defeating the first boar, the second boar can immediately aggro you. This is AI behaviour very similar to almost every other boar.[/SPOILER]