Federation shenanigans would be my guess. If you were on instance B and moderating instance A then instance B admins would have control of your account instead of instance A admins. So if for some reason instance B admins decide to ban that user then they are prevented from moderating for instance A.
Federation shenanigans would be my guess. If you were on instance B and moderating instance A then instance B admins would have control of your account instead of instance A admins. So if for some reason instance B admins decide to ban that user then they are prevented from moderating for instance A.
Or more commonly, if your account is on instance B and instance B goes down, good luck moderating insurance A