My guess is that people who may be having poor performance are damaging the tip of the bullet when they are seating it. its kind of deforming or closing the hollow point tip. The reason that this happens is because Berger bullets are longer than other bullets and so when you go to seat the bullet you may be hitting the top of your die a bit. That is why they have started making VLD type micrometers for redding so it does not do this.
I am not saying that that is what happened to you but it could be. I am pretty certain that with all the hard work that they put in to making the bullet, they have pretty tight tolerances in the making of the bullet.
I have killed only one animal with the bergers so far and it did exactly as advertised. It's very strange that 3 out of 3 bullets did that. Something weird has to be going on.