Printing plate glue? BRAUN 1/1 autograph
 

I recently purchased a Ryan Braun 1/1 printing plate autograph from 2008 Bowman Chrome. The printing plate has a border that is like a regular card. On the right side of the card there is a line of glue or some adhesive that is on the plate but not covered by the border (you can see it if the picture attached properly). I am wondering if other people have heard of this or seen this. I'm not sure if it is a common issue or if I'm just unlucky.

Please let me know ASAP!