I JUST MAKE A NEW FLAT WORLD WITH 53 BLOCK DEEP AND THIS HAPPEN

I just made a new flat world but something strange happened when I spawn,I spawn next to a village I started going to the village but then I saw an oddity there was another random block that was above the grass block I kept watching and something very strange suddenly the blocks start popping up on their own and even the block that appears instead replaces the existing block I even recorded the incident for 4 minutes while recording I also saw another strange thing, I saw villagers like planting in the air, but when they plant in the air the emergence of block farmland along with the seeds that have been planted by the villager this makes me confused and goose bumps, after I thought the recording was enough I turned it off, out of the world and immediately reported it here, is this some kind of bug or glitch? and also (THE WORLD THAT I CREATE HAD I HAVE NOT DELETED)