Placing a stone slab (minecraft:stone_slab) above a hopper (minecraft:hopper) is no longer pulling items through as previous versions allowed.

Also to note, dropping multiple of the same item in a block consolidates the items to a single dropped entity, and not multiple entities.
Tested with chicken eggs, iron shovel, random blocks.

This came up while building an egg farm, and found chicken eggs were not dropping through. work around is to use carpet instead, but this is a fairly large bug that will affect numerous contraptions users have designed (mob farms, passive animal farms, anything that requires a water or lava stream above a bottom sla, etc).