My posts are tight on the fender and the brackets line up perfectly. It's the groove in the posts that seems to be a smidgen wider than the "meat" of the easy brackets. Both sides. So when you grab the bottom of the bags and pull outward, there's a bit of wiggle...
Again, it ain't much, but I thought they would fit tight.
I'm thinking about finding a thin cir-clip or snap ring to take up the clearance. If that doesn't work then maybe shimming one post out a bit would do it....