Armor gui problem

When I opened the armor gui in survival mode, the texture of my armors are not exactly in the middle of their slots. They are shifted slightly to the left.
steps to reproduce
Step 1. Enter a Survival world
Step 2. Open inventory
Step 3. Open armor gui
Step 4. Put on some armor
Step 5. Look at the armors, they are not positioned exactly in the middle of their slots like before.