Am I going insane or was this always the case?

Recently I was messing around with the M2 stinger when I noticed it’s belt didn’t move when shooting anymore. I clearly remember it always moving but I was only able to find this 1 video of it moving: https://youtube.com/shorts/4c7xN820cDE?si=tvdW2xpghrMDUsoS
(Towards the start pay attention to the belt when he hip fires it)

This is a minor thing but I just wondered why remove it or if anyone else remembers it moving.

I never saw it moving like that, just a little bit

Maybe it’s a glitch, because I don’t know why it would be removed