This could be intentional, but it's impossible to play cards like nimble strike or vicous thrust when halted, even if you're just attacking someone in an adjacent square and not moving at all.
It's a tricky situation and we've discussed it a bunch. Jon has summarized it all: And don't take this as anything other than amusement, but before replying I was struck with the urge to shout "Look, Step-card Man! It's the Step-card Signal! Quick, to the Step-card-mobile!"
