Necro Calling Inquisitors - bug or deliberate?

[BB Shockwave]

I found this when batteling a Necromancer Hero in the Dead Land who had Mage troops only (Archmagi, Necros, Inquisitors) and then saw it happen again a few more times in other battles.

Basically, after I killed his stack of Inquisitors, the enemy Necromancer tried to necro-call them, but they were instead of undead, raised as regular Inquisitors fighting on MY side!!!

I'm guessing this could be a side-effect of the Holyness ability? If so, I wonder if this works for Priests and (in Armored Princess) Paladins as well...