If you drop concrete powder onto certain waterlogged blocks, it will replace the waterlogged blocks with the hardened concrete, and doesn't drop the waterlogged block that's broken. These blocks contain : Waterlogged signs, slabs, trapdoors, seagrass, sea pickles, kelp, coral and coral fans, campfires, and all forms of chests. This did not happen prior to Minecraft 1.14, and this works properly with other falling block entities

How to recreate this bug: Drop any color of concrete powder onto a waterlogged block of my list, see picture below.