Heart of the Mists
What was your original location before entering HoM? And yes, possibly a bug.
I have tested and I am not returned to my original location in Tyria if I enter the guild hall while in HOTM, then exit the guild hall back to HOTM.
i.e.
Tyria -> HOTM -> returns me to Tyria
Tyria -> HOTM -> guild hall -> HOTM -> sends me to Lion’s Arch not my original location in Tyria
The game will only remember your last previous map location. Since your guild hall is an Instance, it can’t ‘think’ where you were before that, So the North of Lions Arch is the default ‘drop location’ for characters which encounter this.
This is normal.
I have tested and I am not returned to my original location in Tyria if I enter the guild hall while in HOTM, then exit the guild hall back to HOTM.
i.e.
Tyria -> HOTM -> returns me to Tyria
Tyria -> HOTM -> guild hall -> HOTM -> sends me to Lion’s Arch not my original location in Tyria
Yup, that’s what I suspected and I saw it happening before. It’s like said above, it remembers only your previous location, no more than that and as your previous was an instance it puts you at a “default” place (if you notice the place where you end is “almost” exactly the absolute center of Tyria map).