Graphic bug with Necromancer Minions

During short cutscenes with npc there is a graphic bug occurring consistently;

The invincible icon on top of the Necromancer minions seems to flash in the screen randomly yet the minions cannot be seen during those small cutscenes.
They are seen mostly during storyline cutscenes.
I have 13 minions up, 1 golem, 6 warriors and 6 mages.