https://plays.tv/video/5a7ec13b4399d7ce57/bug?from=user I understand this can be fixed by exiting your whole MC and coming back on, but hey, no one wants to do that!
Pretty much I got arrested and waited out the time. After I got released, the backpack and ammo pouch 'disappears' by not showing up in my inventory. I can still use it, but it just like disappears and you can't see it. This happened to me twice and I assume it does this everytime you get released from jail
Its most likely the glitch away bug, where sometimes items glitch and u have to click the box again to bring it back.