As a long-time judge, and without a photo, I would guess that your fabric widths are not the same width. For instance, do they measure a wobbly 2.5 inches? If it's supposed to be 2.25 inches, it must be that. Watch your seam widths when cutting and stitching. If the comments refer to quilting lines, whether hand or machine, they must be straight. The comments would not be about grain line, but your cutting, stitching, width evenness.
Lay a ruler along your sashing to see if the widths are exactly the same throughout. If not, figure out the problem and make corrections on your next quilt top.
Best of luck,
SandyQuilter