Hold the knife parallel to the ground and up to the light. Looking down the blade as you rotate it slightly you should be able to see waves, dips, variances, etc. I would assume you have some as grinding perfectly even convex bevels the entire length of the blade certainly can be tricky. Not saying they would be or are a problem, but there will probably be some variation in there. Sometimes catching the edge of the belt and you'll end up with a line, some are wide and shallow, others can be deep into the blade. How deep they are is the determining factor whether they will be a problem or not. If they go deeper into the blade than your centerline (where you edge is) then that is a problem. Even if it is fine at the moment, once you sharpen and you hit that low spot, it will open up and you will have a much smaller edge bevel at that spot or have trouble putting an edge on it at all. If your dips are shallow and do not go to the centerline, then normal thinning as you sharpen will even them out and even if they stay they will only be cosmetic. Keep checking the blade while you are grinding before small areas become big problems. Also, doing your final thinning by hand on a course stone can help you even out small holes and avoid problems.