What I expected to happen was:

I expected to see my enchanted diamond sword glowing, but it wasn't. 

What actually happened was: 

The enchantment glint wasn't rendering at all, but I could see in both my inventory and my hot bar that it was enchanted. I was holding a shield decorated with an ominous banner when this issue occurred. Wanting to make sure it might be just linked to shields with ominous banners on them, I tried using a shield decorated with a plain white banner and equipped it in my offhand, and surprise, surprise, the glint rendered on my sword and boots. Still wanting to test if it only occurred with ominous banners on shields, I created a banner with a globe pattern on it, applied it to another shield, equipped it in my offhand, and the sword's glint disappeared, confirming that the issue is tied to shields with banners that have any sort of pattern on them, whether it be the complex illager pattern, or a simple globe pattern.

Now then, my shield was not enchanted and did not have any enchantment glint on it. And neither was my chestplate enchanted, only my boots, and my boots enchanted glint did not carry over onto the shield. Therefor, my issue is not a duplicate of MC-167043 / MC-167477, but it does involve a shield breaking enchanted items enchantment glint.