Nevermind, I found the rule that states "a figure cannot suffer from the same condition more than once at any given time."

However, I stand by the rule that Stun only consumes one action, leaving the target with a second action to perform. Otherwise it's just too powerful and would be houseruled if it were otherwise.

MasterBeastman said:

I'm inclined to agree, and not just because the FFG employees at Realms 2012 apparently said as much themselves (according to another poster.)

If being Stunned made the hero lose his whole turn it would pretty darn close to being Defeated, excepting that the hero keeps his health and fatigue and another hero can't stand him up.  FFG has dropped hints that there are effects which can "defeat" a hero other than being directly KO'd by an attack, which to me begs the question why Stun even exists if it's effects are so similar.  Having two effects that accomplish basically the same goal doesn't sound very streamlined to me.

If someone wants to go digging for an official answer, there's always the Rules Questions link down at the bottom of the page, of course.

 I can verify that at RoT the designers stated that Stun only results in the loss of one action, not two.