Play Zealot, progress through “The Screaming Bell” until you hit the plaza where the statue and second Grimoire are. If you use your dash forwards through the left edge of the circle on the ground, it’s possible to fall through the floor and get stuck in a ditch.
I witnessed it on somebody’s Twitch stream and successfully reproduced it in my own game. Took me about 10 tries to get it in my game.
Haven’t tried it with other classes with dashes so I do not know if it’s Zealot specific. It might only be possible when dashing towards the “ditch” from a specific angle. Maybe something to do with the different elevation of the bricks?