Unrelated but I don't feel like I should start a second discussion. Where does it claim moose goose and moslings "are" for the purposes of the off-screen penalty? I recently had a world where the first boss was moose goose and once I killed the momma I tried to just dodge the moslings while I gathered resources. At one point though while 3 of them (and the nest) were definitely on my screen, the health penalty began kicking in. I have also had times where before I aggro anyone, the penalty is applied with the nest on screen, so it isn't the nest. Is it some invisible "herd" object like the volt goats or beefalo?

Thanks for the report. It picks one of the moslings at random as the boss.