Essence Scarab of Calcification vs Betrayal

Using an Essence Scarab of Calcification together with Betrayal will cause the rare mobs inside the Research Lab to be trapped in Essences too.
While this is technically what the Scarab does, I don't think this is intended behaviour.
These mobs won't drop the Esences either.

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There seems to be some visual bugs with the Scarab too.
Monsters are (visually) outside the Essence sometimes, although you can't hit them until they are freed.

Noticed this bug too while running the essence scarab of calcification and had betrayal on map.

Research lab is full of essence monsters but they do not drop the essences and disapear after the encounter is finished