does that apply to all drilled discs or a specific make?
Ususally hear this with cheap discs designed for the road. They cant take the heat cycling and end up cracking. Anything you get off a trader on here will not do this.
They look like EBC discs to me, but could be any cheap imitation of many, so I would stay well clear. If you want new discs and pads, but a thread up in the Wanted section and the traders will do you a good deal