I was playing 343 Guilty Sparks in a very cinematic motion, but it was all ruined after the Flood reveal cutscene. It was an awkward moment where nothing more than footsteps and reloading sounds played. Not even the Flood made their disgusting growls.
The fx issue.
It fixed itself later on, but it was, regardless, a weird issue that made me feel like I was in an atmospheric environment like space.