The ones I was talking about don't run across the grain, but lengthwise with the grain. I get those sometimes from adding heat to a bow blank and so far they haven't caused any problems for me. The future may decide different, but I haven't noticed any ill effects from them and they don't seem to be getting any larger the more I shoot the bow.
Like I said before they don't show up till you stain the bow, otherwise you can't even see them. They are like little hair line squiggles all up and down the belly, never seen them on the back or ring side of any of my bows, at least not yet knock on wood!