Sometimes, when moving around on Minecraft, the land doesn't properly form (as shown in the screenshots), leaving a blue kind of area, with little white bits. A player can walk on the space as well as other mobs such as villagers, except that they do glitch out, doing this. A player can also walk on the space but it either traps them under the surface (if it's water), or it glitches them out like mobs. It happens rarely though and has only bugged out twice for me so far.
I looked around with 'glitched land' but everyone seemed to be talking about Elytra which is nothing to do with the glitches due to me not ever using one, in the world.
Along with the blue and white dots, it also shows caves and where lava and water flowing below the layers, are.