this is not a duplicate of bug reports with similar names. I did search first.

Sometimes, certain block spaces that appear to be air blocks will be solid. walking into one causes random bouncing and camera jerking at first. if the W button is held, the player will start to take suffocation damage.
a block placed in one of these invisible blocks will almost immediately turn into stone.
when the problem occurs in the nether, they turn into netherack.

effects both singleplayer and multiplayer.
can be caused quite easily by mining randomly with 126 level haste and 126 level speed effects.