It seems you move first and attack after your final location. I tried to Pounce on an adjacent unit blocked from all sides and the unit pounced 2 spaces away from the target, resulting in no attack. In Bounce's case, it means you relocate, get bounced and then attempt to attack but nothing happens.
this is not always true. I have specifically used pounce, knowing the champ had bounce on it, to work as a pseudo-ranged attack and not have my champ end up engaged
Yea, I am going to call this WAI for now. Even if we wanted to change it, it's likely to be a fairly deep level code change.