Shulker box just randomly dissapears after breaking one

I mined a shulker box and went to pick it up, but when I checked my inventory, it was gone. This has happened to me once in version 1.17 and now in 1.20.1 (I would've chosen 1.20.1 in the "affected version" tab, but that was not an option) and I'm not sure what the cause of the bug is.