I made it to the secret treasure on level 5 of Soul Arbiter's Maze on Darksiders II and the portal closed behind me there is no way out. I watched a walkthrough video of someone else and they just went right back through the portal. What happened - is this a glitch?
I completed the game several times, but only once I got to the treasure room, on level 5 of the Arbiter's maze. The scythes named "Black Demise" are just hanging there. I ran and picked them up, then got out. There are some places in the game where portals close behind you, and some that they stay open. I don't remember if that particular portal, did or did not closed for me, but I was able to get out without any trouble.
If it is a glitch or bug, replaying the level might help. Also check if you have all the patches and updates installed, because they fix some stuff about game progression. You can update your game through the Steam platform.