The bug started occuring since the 10mb update which I think was the update before the one that added the cars back to Stable.

It happens regardless of the server played on and it is POSSIBLY triggered by swapping clothes with items already in them and which items have been assigned to the hotbar (1,2,3,4,5... numbers)
Example: have a pistol and some rags in the pants and assign them to numbers 1 ,2 for quick access.
Then swap some clothes (vests,pants,hoodies)
Next-reasign them again and when you press tab to open inventory you also see the hotbar. You can also see the items in the hotbar. Close inventory and some of the items in the hotbar will be apperant, others will not. If you have your pistol assigned to (1) there will be no visual indicator(pistol icon) that such item is assigned to hotbar slot 1 BUT if you press 1 you can get your pistol in your hands as normal.

Read the steps to reproduce cuz its a bit confusing for me as well.