Sorry about the multiple posts, also I guess I already had an account so guesting and being unable to edit was my bad!
Anyway, yeah. My deva refuses to instantly cast spells when fighting the lich in the city gates bar basement, but it fires them off instantly in the bar, in the streets, whether in combat or not.
Err... I have no idea now. After the first spellcast trying to fight that lich being a cast time, now the deva is instantly casting. Lol
edit - it's really sporadic. Sometimes I get instant casts, sometimes I don't.