Time: Always(I forgot exact time of first time, second time was Saturday, April 15th, at 21:12 PM JST)
Context: I used Shadow Tower Portal in a resting room(a room beyond dungeon complete portal) at first arena.
Expected: I expected to go to the entrance of next arena/dungeon.
Observed: Instead, I went outside of the dungeon. Other Trovians went inside and cleared dungeon.
Repro Steps:
1. Go to Shadow Tower(Darknik Dreadnought Mk II normal, I don't know is it happens on hard or ultra).
2. Beat first arena.
3. Press E in front of the Shadow Tower Portal.
4. This happens.

(I'm using costume mods so don't care about my character, and sorry for my bad English)