Been getting this more and more in PVP, originally on Templar being unable to fire Radiant Oppression on players but getting it with Sorcerer casting Crystal Fragments where the casting animation plays but the spell projectile stays by my character with no magicka consumed and target is unaffected.
So far I've only encountered this when there are groups of players making it hard to note name of player and they don't remain unattackable, usually between 5-10 seconds
Dovie'andi se tovya sagain.
Niidro tiid wah fusvok dirkah.
aka.
@Cuthceol