I ran into an odd situation and am hoping others might be able to duplicate it. If it can be duplicated then we should report it to Blizzard.
I decided to start a new character, Blood Elf and got the 10 PVP weekly. I have discovered that if you do the PVP battles in Silvermoon, Eversong Woods, or Ghostlands any wins do not get credited. They do get credited in your achievements, but not with the quest. I did battles with the character from level 18+ in both Undercity, Org, and the aforementioned zones. Only in the BC areas did I not get credit.
If anyone else feels like trying this out to confirm I would appreciate it. Also if anyone wants to try on the Alliance side BC zones (Bloodmyst Isle etc), that would be useful too.
While generally not a big deal since most people pick up the quest in Org or MoP cities, it was a surprise since I got the quest and then hearthstone back to my starting area.