My guess, without knowing more about the game you've made, is that you have triggers across many scenes, but no way to transport your player among them. As a result, the player can only access the triggers in the scene where they start.
Another guess, that you're not hitting the save button after setting the QR code. It can be a bit hidden there at the bottom of the panel.
Again, I don't know if these are your difficulties, but thought I'd guess. If not, see if you can tell me more and share screenshots of what you've got in the editor. I'll try to keep sleuthing.
Finally, you should know that most people are likely no longer listening here. There are some new forums at
fielddaylab.org/forums. You can sign in there with your ARIS account.