There appears to be an intended relationship between Resilience and CotU specifically, perhaps because they are opposite aspects of the Gangrel's nature.
The book calls out Resilience specifically and not just magical or unnatural armor. To allow mage armor to block it would be no different from allow Blood Sorcery to the same.
The only work-around I could see happening is if the Mage uses Death school to craft a spell to specifically mimic Resilience.




Perhaps the Death specialty spell could animate the Mage's body in a similar way to how Vampires...