Hello and good day.

The bug is that you can manage to put items into a clothing item that you have stored in your inventory, which should not be possible.
This is abusable to gain extra inventory space (eg for hunting jacket, that has more slots inside than it takes up)

Situation: full inventory. In it (important) a raincoat, a saline bag, a protector case. Inside the protector case a binocular and rags.
Binoculars are 3x3, saline bag is 2x2.
Put protector case into hands, then drag binoculars onto the saline bag that's inside the inventory (swapping, light blue box around the item).
Result: the binoculars are now in the raincoat, which is inside the inventory.
But it should not be possible to have things inside clothing inside the inventory.