When I created a new world and I entered, but I see next to it that there are no blocks under the grass block. After a while the grass disappears.
MC-121569
World generation problems
Resolved
Duplicate
0
montlikadani
(Unassigned)
Unconfirmed
block, world
Minecraft 1.12.2
Retrieved
These are common glitches, Simply place a block next to all the grass and they will disappear.