Skull problems

So I was always playing with one of my friends Halo 2 with the Bandana skull (the one that grants you infinite ammo). But now it suddenly disappeared and I can’t find it in the skull menu. And I think this problem happened before in other Halo’s but since I only used in Halo 2 I always ignored it.

It’s also not only the Bandana skull that disappears, I once played with my friend also using a skull that multiplies the explosion radius, but now that I find it annoying I want to remove it or deselect it but I can’t find it in the skulls menu either, so I’m stuck with it. What can I do?