UPDATE: Apparently the bug was being caused by massive lag with a buggy mod combined with server stress, and it was not an issue on the official servers

This has occurred several times to me, albeit on a modded server, so I'll have to go and try on an official server and see if I'm still getting the same results

I'm pretty sure it he's referencing the 0.63 branch, as it happened to me one point the last time I was playing on a fresh spawn running around Elektro on a medium population server. I was getting shot at without hearing any supersonic cracks or gunshot sounds, and there was no angle for me to get shot at from a distance where i would not even be able to hear a suppressed weapon.

Sorry about "spamming" the bug feed. I don't use reddit, nor did i see that link anywhere on my way to the site

I've had this bug happen to me before while looting a police station. I had plenty of inventory space to remove the mag and even put the gun itself in my inventory, but it still was bugged. It had an empty mag in it and even with the gun in my hands the icon of the mag was crossed out and I was unable to reload it using hotkeys.