The bug
If you try to look at items, clouds, water, item frames, paintings, armor stands, mobs, the player, particles and transparent blocks through a charged creeper's armor, you'll see that they all become invisible.
Command to reproduce
/summon minecraft:creeper ~ ~ ~ {NoAI:1b,powered:1b}
Expected result
The mentioned graphical elements should be rendered behind charged creeper armor.
Linked issues
Attachments
Comments

That's actually the graphics I had when testing
Can also confirm. It also affects the "wither's wither armor effect" too.

Confirmed for 1.16 Pre-Release 7
The player doesn't become invisible for me
Can confirm in 21w16a.

Affects 1.18.2 with boats:
[media]

I just noticed that wither armor is tracked separately.
Can confirm in 1.19 and 1.19.1 Pre-release 1. This issue can be reproduced by executing the command provided below and observing how transparent blocks, clouds, water, particles, and entities, don't render behind charged creeper armor.
/summon minecraft:creeper ~ ~ ~ {NoAI:1b,powered:1b}
Can confirm in 1.19.2.
Confirmed. It does that even with the Graphics set to Fabulous!