Cracked Granite

I have a Customer with a Dark Blue Pearl Kitchen Counter
It formed a crack 6 months after installation. It was 5" long, not completly through and (http://maplered.com) ran from the front polish edge back toward the back wall.

The Counter (http://GialloFiorito.com) was replaced and (http://maplered.com) developed a new crack near the same location with an addtional crack near the undermount sink.
I know the 1st though is someone stepped on it, but I beleive this isn't the case. We checked for straightness & level, its was good.

I've sold Granite for ten years without enCounter (http://GialloFiorito.com) ing this situation.

What would cause the delayed problem?
It this a Fabricator or Homeowner Problem?
Anything different about Blue Pearl? Everyone tells me it is very dense with little problems. Though I don't know what they are refering too.