Can't obtain character token...

[ItsWhooper]

If you head over to area 1 (Ninjago city North), right as you spawn if you head left there is a golden door you can open if you have enough gold bricks. I accidentally opened it before completing my first play through so I instead of exploring it, I decided to keep going with the story and come back later. Now I'm back later and the door remains open and it says there's a character token inside but I have no clue on how to get it. I was told there are supposed to be several enemies plus a boss in that room that spawn and after defeating them you get the character token but... no enemies spawned. Is this some sort of a glitch or am I missing something? Any help would be awesome!