I'm having a strange problem with a part built with a 'master' part. I built the Master part (called '... Skeleton') and inserted it into the derived, or actual part. I built the part and everything when file. Now when I open the part, 3 of the sketches that are derived part references are 'shifted' down in the derived parts. This moves the features and causes the part to fail. I've tried 'editing' the Skeleton Part feature in the derived part but that doesn't help. The only thing that causes the sketches to move back to the right location is if I 'edit' the Skeleton part and de-select "un absorbed sketches", rebuild, then select "un-absorbed sketches". The problem with this method is it breaks the references between the sketches in the derived part and sketches in the Skeleton.