I was editing my x32 resource pack when i noticed that ui elements and 2D items in the inventory and in the hotbar are not displayed correctly. On 1366x768 and lower resolutions they are just fine but on higher resolutions they look kinda distorted as seen in these images.
For an example i have the invertory ui and as seen in these images icons where you place your helmet, chestplate etc. are distorted on the 1920x1080 screenshot. Sorry if this was reported earlier and if my explanation is not very good.
EDIT: The distortion only appears on GUI Scale: -1 on GUI Scale: 0 it looks normal.