When mining out an area without picking up the blocks mined, I will normally place blocks and the blocks that havent been picked up will jump to outside of the new block fairly quickly. I was just doing this, mining stone and cobble stone, and placing soul sand, but the mined blocks that were not picked up and had soul sand placed over them did not cause the mined blocks to "jump" to an air space outside of the soul sand. Seems like a minor bug but this is my first time reporting one, so feel free to email me with any questions etc. Hope this helps!