Not sure if this is a bug but a neutral goblin calls evil mounts.

Also, possibly related, cabal outer and likely inner will attack your mount if Orcs are raiding and you’re in the same room.

All the animals the goblin calls seem to be purposefully evil.

Your called animals are of the same cabal you are, so outers/inners hitting them as an "ally" of your similarly "caballed" ally makes sense.