You would expect when you pickblock an empty shulker box with more empty shulker boxes in your inventory it would act like it does with other blocks and put a shulkerbox in your hand, instead the game doesn't do anything as if you had no empty shulker boxes.
 
Recreation:
1: Grab two shulker boxes in creative 
2: Go to suvival
3: Place one 
4: Don't hold the other shulkerbox in your hand
5: Pick block it and observe no change
6: Cry cause it's like beta again
 
NOTE: Might only affect placed amd rebroken empty boxes, I haven't tested yet.