Not really. That has to be a bug in kbin, not a problem with Lemmy. Lemmy allows admins to delete stuff off their own instance, but kbin shouldn’t be just accepting that as a mod action from any admin on any server it’s federated with. That doesn’t even make sense. I assume it’s just a weird interaction of different ways of handling things on kbin and Lemmy.
It’s invalid, not invalid. You have the emphasis on the wrong syllable. English is dumb.