Gas mask bug

[tjockblock]

So, the first time i used the gas mask, to get through to the computer terminal, it worked as intended. But i noticed the Gas Mask gone after a while. So when i was going though the other place needing a gas mask (the place where you need to change pipes) i couldn´t get through. Checked walkthroughs everywhere, but it says i should have a gas mask there >:

Anyone have this problem or know how to fix it ?