Beefalo vs Buzzard-Lack of defence response from Beefalo

I noticed a bug in DST while basing in the Desert. 

Some meat dropped from a hound attack near some Beefalo, two Buzzards flew down, and because the Beefalo were close to the Buzzards, the Buzzards attacked the Beefalo. 

However, the Beefalo just stood there in their grazing mode, not responding to the attacks of the Buzzards. 

Thanks