I had this exact thing happen last night on experimental (6/10/17) with an added issue. Once the clip disappeared I dragged some .22 ammo to the quick bar and tried to reload to see if the clip would reappear. Instead it caused an infinite reload animation loop. I relogged and it fixed it. Clip reappeared after that and was fine with the addition of several single rounds (from reloading before logging) appearing in my inventory.