Guild Wars 2

As the title says, the traits on my elementalist keep resetting itself every time I log in

This keeps happening to my warrior. The first time I thought it was just a mistake and I forgot to retrait after resetting them. I soon discovered it happened again. Its now happened four times, each time following leaving the Heart of the Mists.

This happened to me also but its not a bug as far as I am aware. Your PvP trait setup is only for pvp, once you leave the mists it reverts to what you had before you entered.