Unintended(?) Amumu Passive+Immolate Interaction

Didn't see this anywhere else so imma post it. While Amumu's passive is applied to a monster it causes Cinderhulk's Immolate passive to deal lethal damage to monster camps past 1 hp, most likely due to the fact true damage cannot be reduced. Replicated it in the Practice Tool a couple times with the same effect every time. rip donations