When I updated my Snapshot Testing world from 1.14.2 to 1.14.3 Pre-Release 1, I was trying to pick up a Shulker Box, so I switched my gamemode to survival and broke the Shulker with a pick axe only to find that the entitie didn't drop.  I proceeded to break grass and sand blocks to see if I just did something wrong with the shulker and well no entities drop from any of the blocks.  I wondered if this was a glitch across every world, so I loaded up a new world and when I broke some grass and wood blocks they dropped their entities.