I think it would be really cool of 343 to patch this problem where the “Secret” ammo crate at the end of Pillar of Autumn is not there as it would have been on the 360. In case anyone hasn’t looked down the canyon, you can see that it fell down there. My best guess is that, for whatever reason in this version of Reach, the shockwave from the MAC gun firing may be what is knocking it out of it’s hiding spot. I’m pretty sure that 343 was attempting to present these games as close as possible to how they were originally (but prettier). Maybe they could fix this for us.
I’ve had it where it is already out but still accessible, so I don’t think with it falling down is always a common issue.
This one?
https://twitter.com/Comedic_Hermit/status/1205892691822882817?s=20
If it’s consistent you can file a bug report on the support site.
I created a short (albeit unexciting) video on that.
To summarise, every time you go through the area there’s a small chance (17% from my testing, your mileage may vary) that the cache will be forcefully ejected before you can reach it.
I don’t think it’s related to the MAC because A) The MAC doesn’t seem to fire before the weapons crate is ejected (when loading from the Rally Point) and B) If the crate stays in the wall and you interact with it (melee, shooting, etc.) it will be launched into or over the canyon at speed; this is either impossible or much less common on the Xbox 360 version.