I have on occasion gotten an inquiry from someone that has just received their holster mentioning that they had noticed and was concerned that there was either some stitching missing or that the leather was coming unglued on the upper slide-side of the pocket.  There is nothing wrong with the holster. The holster is made that way and the following is an explanation.

I have intentionally not sewn and not glued the last 1/2 to 3/4 of an inch or so of the slide-side of the pocket on some of my holsters so that the back anti-print panel can be bent backwards to facilitate drawing the pistol from the holster.  If this area was sewn all the way to the top or end of the leather piece the back anti-print panel would not open or bend backwards enough to allow an easy extraction of the pistol.  On some of my holsters the area is sewn all the way to the top of the leather piece but the last 1/2 or so is cut out to do the same thing to allow the back panel some bending room.

All my holsters have always and forever been made either of the two ways described above depending upon the particular pistol intended for that holster.  This DOES NOT cause any problems nor has there ever been a problem with the pistol staying in the holster.  The holster is plenty deep enough and the molded leather also helps to retain the pistol.  The photo below shows the area discussed.

CAUTION: Unload your pistol before practicing your draw.
  ALWAYS make sure your pistol is seated properly in your wallet holster before putting it in your pocket.
  NEVER carry anything else in your pocket with your pistol and wallet holster. 
Also NEVER holster your pistol while your holster is in your pocket!