Starting with the introduction of RenderDragon, UI elements are affected by anti-aliasing. This causes unwanted side effects, such as blurry menus and problems with transparency, such as the crosshair losing transparency, staying completely white, and the hotbar rendering differently.
How to reproduce:
-Set the anti-aliasing setting to x1. Observe the various UI elements.
-Set the anti-aliasing setting to x2 or higher. Observe the same UI elements again.
Menus look sharp. The crosshair is transparent and inverts colors. The item hotbar maintains its proper transparency.
Menus appear to be blurry. The crosshair is a solid shade of white and does not invert any colors. The item hotbar transparency is altered.
MCPE-58826 is a consequence of this issue, but the issue is not exclusive to the crosshair.
Refer to the attached images for a visual representation. Zoom in if the differences are hard to spot.