Essence Stability unexpected behaviour with Remnant on Deafening

Hi,
Sometimes when an imprisoned monster contains only Deafening essences and a Remnant of Corruption is used on it the monster simply becomes Corrupted with no transformation, despite the Stability scarab specifying only upgrade or transformation.

Given that the upgrade is impossible it seems like the essence should only transform in this situation. Perhaps the upgrade is chosen and fails or perhaps the remnant does nothing, but either way it seems like the scarab is poorly worded or something is going wrong.




Thanks