No its not a memory issue, There is a small hole in the VC in the location I've stated. Look for yourself, while your moving, at the spot I've described and you'll see it quite clearly. On the left Fmc at the letter Y, there is a screw right next to it, look just below the screw as you are moving or going over lighter colored terrain and you'll see what i'm talking about.
Just for the record, PMDG have repaired many holes in their aircraft's VCs. There is still several present in the MD-11 but will probably never be revisited.