I have been having this issue since the launch of 1.26 *When the developers added the parameter in the files for guns to be able to spawn with one round in the chamber. I believe this was 1.26 if you want to see and diagnose this issue much closer. I believe it is directly related to the coding for the shotgun ammo and it also correlates to shotgun ammo appearing outside of the shotgun model sometimes. This also includes the M87 Grenade Launcher but because that gun doesn't have a conventional reload function *(Cycle to eject and cycle to reload). But whenever the game thinks there is a phantom shotgun round in the gun it creates a ghost bullet that causes terrible desync. If you were to artificially downgrade your network connection to have a worse UPLOAD speed such as mine (2Mbps Upload speed to a distant server halfway across the world) The rest of the game runs fine but when the ghost shotgun slug is created the game cannot reconcile and stops working. I can receive damage from enemies and zombies but I cannot shoot any bullets from any guns. They are simply non existent. What's even worse is that during this specific desync you cannot leave the game. The lobby will NOT count down. It will make you sit down and see the grey screen but there will be NO count down. You have to force close the game and re-log. I have gotten this glitch consistently for about 3 months. There are other users on reddit reporting the same issues. Please fix the shotgun ammo desync issues. I believe it's tied to the spawn with round=X parameter added in 1.26 if you can just revert that change for shotguns and the M-87 launcher you can probably fix this issue internally later instead of having this game breaking bug preventing people like me (and some other lucky people that I have told about this phantom glitch) from picking up ANY shotguns. It happens a little less with the Saiga in full auto because the game files are uploaded sequentially pretty close together but the farther the spacing out for reloading and shooting the likelier it is to happen.
To replicate the glitch, Limit upload speed for Client to server, Play on a distant server to the client. Use all shotguns and shotgun ammo types while reloading. Set up a shotgun deathmatch on Sakhal military zone to experience true lag city! Then you will be guaranteed to experience it. The textures in that area need to be optimized for console soon.