I've got one in my Prismacolor box that's been broken since I got it and I got the sharpener at the same time as the pencils. Now the wood on that pencil is cracked down the pencil too but as it's sharpened down so much I figured there wasn't much point in trying to get a replacement. I did read somewhere recently that if you place the pencil somewhere reasonably warm the wax softens and the breaks can fuse. That might be worth trying?
I do have the Prismacolor Premier sharpener. That one gray pencil just breaksMaybe it's just a defective one.
The specialist sharpeners definitely make a difference I think. I get a much finer, stronger point for the Prismacolor pencils with the short tip option, and the wood shaves much more finely with the really sharp blades. I also have a Derwent sharpener now and that works similarly well but was much cheaper.