Swords lack top texture when in use

What happened:

I was trying to test out the new "Illager Raiders," and how to get the banner, when I stumbled upon a glitch with a diamond sword. When swinging at the mob, the 3D model used in the UI had a missing top texture.

How to recreate:

To recreate the glitch:

1. Try and swinging a sword at a mob.
2. look at the sword swinging animation.
3. try and record, then slow down footage of the sword swinging.
4. you should be able to see that the top of the '3D' model of the sword is missing.