When azalea trees generate sometimes the rooted dirt replaces grass blocks on the surfice creating odd patches of dirt and rooted dirt.
(Sorry for screenshot quality my windows shift s doesn't work)
Seed: -2802382815000627384
Coordinates: literally 10 blocks from spawn
It is an element of the Azalea Tree feature, and it is as expected to see these blocks on the surface beside Azalea Tree.