weapons in backpack "dont exist" when equipped

when i equipped any gun(minigun,sniper,shotgun,launcher) ,all cards or grenade from my backpack it didn't show in hands. The image of the item is on the hot bar but once its " pulled out" there is nothing there.  i dropped on floor and picked back up a few times, still nothing was there. so, i tried to re skin in repair bench and once i equipped and switched to the item it kicks me with lots of red words in the top left. tried three times to ensure that was what was happening. reported to admin and he said to report. so far has not happened again  i play in survival US , if it happens again ill record or photo