When you attack the Roathir Cerulean Base in the legion mission Roathir: Hostile Takeover, it "[w]ill sometimes use its scattering array, boosting its defences by 50%. This event stacks."
Problem is, when the defense gets big enough (we're talking ~3.6E+17 big), it breaks; it acts as though the base had no defense at all:

I'm guessing the same issue will occur with Illuciar, Bane Phantasm.