HOW TO REPRODUCE:

1.find a 1-block tall flower (dandelion, poppy, etc)
2.stack snow on it to layer 8 (full block)
3.destroy the dirt/grass block UNDER the snow and the flower in it
4.the snow floats (another bug?) with the flower IN it. Destroy the snow
5.the flower floats. it will randomly pop out over time or immediately when it receives a block update