As per title. An absorption hopper can put a shulker box in another shulker box. This is possibly exploitable to perform an NBT packet chunk ban (though actually doing so would be very grindy).

i just tested this and it doesnt work.

I can't reproduce in the 1.16 version either. Is this happening in an older 1.12.2 version?
*Edit - Nvm I re-read the issue title , I still cant reproduce this.

Hm. I was using a Diamond shulker box from Iron Shulker boxes.

Ah, ya, there we go, its a iron shulkers specific problem, ive been told he is fixing it on his side.