When going to the nether, equipped armor does not show in the armor bar

When going into the Nether with some armor equipped, the armor does not show up in the armor bar above the hearts where it normally would. The armor bar is completely empty, but in the inventory the parts of the armor you wear is shoen in the correct armor slots. The armor does show up on the skin of the player if you press F5. The armor protects you as it usually would, but as said is not shown in the armor bar. See attached screenshots for visualisation.