The boar is too far from where you found it, probably. Every time, after H&H, I've brought a boar from farther than the render distance it's kept running back and forth along the wall closest to its roaming location. Moving the pen wall has always resulted in the boar simply adjusting the spot where it runs.

Really annoying. In my current game I was super lucky and star boars spawned right next my base after I'd built it.

It worked fine prior to H&H.