Sometimes, units try to (endlessly) go out of the world, like they’re looking for something.
Apparently, only land units are affected by this bug.
Thanks for the report SlenderBadger98!
This issue is now being tracked.
You’re welcome 
Here’s another screenshot, belonging to an AI game I played last night, in which the bug occurred once again, to a villager:
build 38862
This bug is very frequent amongst villagers…
WELL this is is just creepy… its like… there is something beyond the darkness beckoning them! 
In my last custom game with the AI, I got this bug plenty of times. Since they are constantly “moving”, they can’t be selected with the “idle villagers” command:
I think they are just ahead of their time and figured out the Earth is round and can get to their destination quicker by going the other way 
Well that’s one way of getting out of having to do menial labour
Issue affects armored elephants as well (build 38862)
It’s still a bug in patch 46777.
You can see a Legion and a Helopolis trying to get out into the void.
The bug affects at least these units:
You’re gonna have to add priests to your list.
The priest wololo’d the legion and helopolis into jumping off the edge.
I’ve never had this bug with any of my units but this issue seems prevalent with the AI.
Seriously? Maybe you just didn’t use enough villagers to reproduce it. Try 50+ villagers working on wood, and you’ll probably encounter the issue at least once.
I only play DM so I only have to train about 50 villagers.
I guess the issue is not that frequent, then. In build 38862 I think 1/3 of all matches I played had it. Now maybe it’s less likely to happen. But I still think it has a randomness factor.
