Falling through the map when you're feared. It is a super old bug that I remember way, way back in old school vanilla and tbc emu.
Well it happens on Lordaeron too,.
It's super annoying, and ruins my gameplay experience.
Edit: let me clarify for any people who know how to make github pull requests or commit.
In Azshara There are ghosts named Highborn ApparitionsThat cast Fear.
Well due to the terrain being very hilly in their area, The player end up running away into a slope and falling through the map to their death.