Shulker head appears while Shulker Box is invisible

I was trying to make a 1 command creation, it included Shulkers as part of it. Since Shulker's hitbox is the size of a block, I wanted to give it a glowing effect as to make it look like the edge of a block was glowing, I would make the Shulker invisible so you couldnt see the Shulker. But the head stayed visible. I tried re-logging but nothing seemed to fix it.
I have already looked up this issue online and saw a very similar post about the same problem that said it was fixed, but it wasn't fixed for me.