Since I've found a couple more areas where it's possible to leave the bounds of the world, I'll collect them here instead of creating a new topic for all I find. Feel free to add yours' as well.

Holding Cells:
Underground Shrine:
Torture rooms view 1:
Torture rooms view 2:

(Also posted the following in its own thread):
Ship north of Braccus' Armory:
Ship north of Braccus' Armory onboard:

Last edited by Aerlynn; 22/09/16 11:01 PM.

Screenshots gallery of some of my Original Sin 2 Early Access bug reports: