I received my Codex Deluxe set yesterday.
Haven't inspected all items yet, but opened one of the deluxe mat rolls.
It looks like during packaging one corner of the rolled up mat was folded back when it was inserted into the plastic packaging sleeve. When laid flat, the corner is lifted up about .5 inch in elevation in a triangle with a hypotenuse of about 1.5 inches from side to top edge. (from memory so accuracy is in doubt)
I've reversed the roll and packed it back up until I have more time to look at it. But it did have what seemed like was going to be a permanent dog ear situation going on. I've googled how to solve this problem with mouse pads and will try light heat from a hair dryer on low setting or an iron on low with a buffer followed by the application of weight on a flat surface.
I wanted to see if others have had the same issue, and if they have been able to remedy the problem.