It may simply be an artifact of your camera, but it sure looks like that left stud is bent slightly away from the other stud. Measure the distances between the two studs with a micrometer at the bottom of he studs, then take another measurement near the top to see if they are equidistant top to bottom.
Also, when installing brush plates, they are generally a very tight fit, so cocking the brush plate, even slightly clockwise as shown in your picture, will compound the problem.
Make sure the brush plate bottom side is parallel to the commutator surface, then with fingers, squeeze the tops of the studs together. That may do the trick.
George
