On experimental—much more than 1.09—your hands become bugged so that you cannot switch weapons or put anything in your hands. This occurs after switching weapons or using something in your hands. Usually it appears that nothing is in your hands, but you cannot pick anything up or put anything in your hands. You must relog to fix the issue, and when you do, you find that an item previously in your hands is still in your hands, but you can now switch it out.