Twitter friend, Mike, created a shield-like shape (below) in Illustrator and had some issues when scaling it down. The shape was built with multiple polygons that all aligned beside each other to form the final mark. The seam in between the individual shapes caused the issue. Even though the vector paths were touching, the background color pierced through where the shapes met.
To correct this issue, we need a solid background shape and a few less individual shapes, ultimately producing fewer seams. Take a look at how to fix we can fix this issue in the video below.
Voila, no seams!
After sending the video to Mike via Twitter, David jumped in and blew my mind showing us the Shape Builder tool. I'll definitely be adding that to my Illustrator arsenal, as should you.