Glad they found out what it was. I've been a machinist for 30 years and worked on all sorts of different castings. Sometimes a pour doesn't flow through the mold exactly as planned. This is the sort of thing that can slip thru even a solid inspection program. I wouldn't expect any other problems related to this, since the casting for the block wouldn't affect any other systems on the car. Anything else that would be affected by that would have shown up already.