Whenever I broke a shulker box and opened it at the same time, the player inventory became in-accessible, but I could interact with blocks but not open the inventories of blocks. instead it would open the chest/shulker box and it would be visually be open, but in the case of shulker boxes, they would actually affect the world due to them being open. I haven't experimented with it, but it has done some weird things to the game, (the chests/shulker boxes stay open even after logging off)