Halo 4 weapon despawning

I was playing H4 campaign “Reclaimer” on Legendary and was going into the Forerunner facility after the sniper canyon when my secondary weapon despawns itself. That supposed to be a thing? Despawning your weapons that you are HOLDING onto mid level?

Was there a cutscene or loading screen when you entered the facility? Sorry, that’s one of the levels I don’t recall 100%.

Not right when I entered the facility. It’s the part after you run through a few jackal snipers on the cliffs, cross the bridge and kill a few Prometheans. It’s the part where you enter the facility, walk a little and then you meet the Librarian. I still kept my primary weapon after the cutscene with the Librarian.