Is this the same way with Errende 
Having 2 should give 2 separate chances to proc Pnuema or is the 2nd Errende disabled 
Let me check. What I said a few posts earlier only goes for additional item drops, not autoskill casting.
EDIT: Autocast cards should've never stacked to begin with (if it's the same cards; different cards do give two chances at casting the skill), i.e. the 2nd Errende is disabled.