I've noticed when using the defend skill (the one you get with the shield,) it brings up a casting wand, but there is no applicable square to "cast" in. Eventually the system figures out that a selection isn't necessary (or my tapping of the space bar and frantic clicking registers) and moves on.

I've only seen it when champions use the skill, not units.

Maybe there should be a stikied thread in this part of the forums for this kind of issue?
Since it might be bound to raise its ugly head time and again during the beta.