Has anyone experienced a situation where backstab refuses to work even when behind a mob and with enough energy? It doesn't happen all the time but it's frequent enough to be a noticeable nuisance. I'm behind the mob spamming backstab at < 35% but keep getting "Not enough energy" messages while watching my energy cap and thinking wtf?
I just want to know if anyone else has experienced this so that I can rule out me being retarded and/or crazy.