Well ya got me then, sounds like a glitch if it is still running loose in the world.

To me serious boar farming is best done away from your main base. Once you want to get a 2 star it is just much easier to set up an operation near where you find them connected by a portal than to try to drag it back you your main base. Also the boars will be much safer away from you, only being in danger when you are in their presence.