I have now lost 2 battles in Monkey Magic because i thought it would discard before Jump Back triggered. The text on Staggering Blow: " Immediately discard the two oldest revealed cards in target's hand." And Immediately has this reminder text: "Immediate effects take place before blocks" I know dodges take place before blocks. But the Immediate keyword really sounds like it should happen before dodges as well.
The way I remember it is that dodges and the like stop an attack from hitting you at all, while blocks negate it. Of course, it's still weird wording.
Staggering Blow is not bugged, but I agree it can be a bit misleading. FAQ has a detailed anatomy of an attack. "When targeted..." cards (eg. Dodge / Jump Back) trigger before blocks and immediate effects.