anything other than brake judder when braking in reverse is probably due to the ABS readjusting itself to function in this direction, or something to this effect. This is what I've been told. I believe this is also normal. You should've had this happening to you even before you did the brake job. This has been happening to me for years and it doesn't happen all the time. It seems it's reverse speed- and level of braking effort-dependent. Others may want to comment on this.