[masraum]

could be car out of balance (corner balance) or it could be that things aren't bled evenly or on of the calipers is somehow different than the other (stiffer or something) I have heard of the new seals being so tight and stiff that they pull the piston back slightly when you let off of the brakes. If one was doing this and the other wasn't that could cause weirdness. Before you worry about any of this I would try some stopping exercises above to check things and be sure it wasn't a fluke or a result of the road conditions instead of the car's condition.