Under the Map Act 10

Found it randomly in that spot on Act 10 on my SSF SC account while leveling.
Don't believe you can run under the map, it's more of a "hole" that you can go in and out of.

Posting a gif to reddit too, will edit with link.

Edit: Reddit video link of it: https://dd.reddit.com/r/pathofexile/comments/7t9mrl/bug_under_the_map_o_o/