In Java Edition, the collision box of a shulker box changes when the shulker box is opened. One easy way to see this is by standing on top of a shulker box that is opened. However, in MCPE, the collision box never changes.
- Stand on top of a shulker box that has been placed right-side up.
- Open the shulker box & close it.
- Notice that you never moved up or down.