Iron Box disappeared from inventory (game breaking bug)

[emreDZ]

[POSSIBLE SPOILERS]

When I reached the ice wall the game told me to go back to the general store to check if I missed anything. I searched the area several times and realized that I needed to open the iron box that I've found near the start of the game. However I can't find it in my inventory, nor is it in consumables. I am pretty sure that I've seen it in my inventory more than once throughout the game. It must have been disappeared at a certain point. Saving and loading the game does not help.

It is a game breaking bug because I can't make any progress in the story without having opened that box. It won't even let me through that ice wall.

I've spent 7 hours in that game and I don't want to restart it just for a bug. Is there any way to fix this? I remember seeing something about this issue in one of the patch notes, apparantly it didn't fix anything.

[|BE| Vakonof]

Have you picked up the key?

[emreDZ]

Do you mean the key in the envelope from general store? Yes, I have picked it up.

[Jean-Francois Fiset]

Did you try to reload and go back to the wall? The letter from the box that is needed to go through should be in your inventory on reload, so you should be able to go beyond the invisible wall (unless you forgot something else at the store/doctor's).

[Zombra]

I'm very confused.

So the key I found in the mailbox automatically opened the "small box" I've been carrying around? (Why didn't the game let me try to open it from my "consumables" inventory like I have been trying every time I find a key?) Have I been carrying around the gun in the small box this whole time? Or did the small box only have the partial Hamilton Letter inside of it?

What exactly was in the small box and what exactly was in the mailbox?

EDIT: Never mind, I figured it out from careful reading of my journal. It's definitely very weird that the game skips past the opening of the box.