Note: This is a visual glitch only

I was messing around with the new mechanic of the shulker duplication, and later came across that IN my inventory, the shulker box item itself was as if it was open, and when placed it appeared open too. When opened in this state the top opens more, somewhat acting as if it was double-opened.

I was in my world, and I was showing the glitch to someone, and placed a shulker to show what it's supposed to be like, and it got fixed. Sort of. After that I noticed when the shulker is peeking out of its shell, the shulker boxes open in the same way, even in my inventory.
To recreate this, you first need to get a shulker to open, exit the world while it's open, and log into another world (without real shulkers), and then the glitch should happen. If it doesn't work, you may have to do the new shulker duplication beforehand. (When a shulker is hit by a different shulker's bullet, the shulker creates a new shulker)