This is currently a issue in stable and i believe exp as well. It's also been a long standing issue in DayZ. This mostly happens with explosive grenades and feels like a desync issue. Spamming to throw grenades as fast as possible will often lead to getting stuck with "ghost grenade" in your hands and no ability to switch weapons or get out of the in between state. This could be an issue where network issues are also happening as it seems to happen more when the server is stressed or a lot is happening in that bubble. Fairly annoying as it quickly kills your ability to do anything besides running straight at enemies and ending your Schrodinger status. I know friends that it has happened to as well as random players.