When you bookmatch wood, you will get an exact copy with perfectly quartersawn wood. If the grain is tilted slightly it can reflect light differently, which is why the degree of color can vary as the light reflections change. Color differences or streaks, common in red spruce, are just part of the natural wood. Bearclaw too, though what caused it are likely very different. The bearclaw in my D 35 was in 1970, a flawed piece of spruce and thrown into the cheap guitar stack when graded. It is only due to the vagaries of fashion that some seek it out today.
Everyone has their own limit as to what they tolerate. Some will not tolerate red spruce with any streak at all, and that is one of red spruce's defining characteristics.