In Minecraft 1.14 when falling block, that is not affected by gravity, falls on top of a shulker it solidifies and turns into solid block.
But in Minecraft 1.15 any falling block breaks when touches shulker, even when it is not affected by gravity.
This breaking behavior is good for blocks like sand, but it doesn't make that much sens for something like bedrock and other "not gravity affected" blocks.

Used command:

/summon falling_block ~ ~ ~ {BlockState:{Name:"minecraft:bedrock"},Time:1}