Pain Offering with Unwilling Offering passive doesnt work on some monster types

Description of the skill and Abyss Lich passive:

• Pain Offering: By using it you can sacrifice one of your skeleton to grant all your minions in range of 6 meters from you increased attack and cast speed and also additional damage for 6 seconds.
• Unwilling Offering is a notable Ascendancy passive skill for the Abyssal Lich that modifies Offering skills. Offering skills can be used on enemies within Culling life threshold instead of your minions <...>

— when attempting to sacrifice a huge elephant (sorry, I don't know the name of monster), it died literally in 0.02 seconds (after one frame in 60fps video) after casting the Pain Offering, as you can see in the video frame-by-frame:

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https://youtu.be/18semINUVJ8

Note: I'm really hoping for a buff to the Abyss Lich's Unwilling Offering passive: without a unique support gems that makes victim immortal, this passive is simply useless, as victim dies from my subsequent attacks. In the video above, victim didn't die from my attack — the Bone Cage had disappeared by then.