Random Suffocation

-I was simply sprint-jumping across a plane toward a tree (did not reach it) when the screen changed to stone and I began to suffocate. The only stone nearby was beneath the dirt below me.

-I could not mine it away, and was unable to change gamemodes. I received a death message along the lines of "Niknokinater suffocated in a wall.

-Upon returning, I found everything from my inventory scattered along the floor as well as atop the tree. The area around the tree (after collecting each of the items), was horribly lag-riddled (after restarting game, area is no longer laggy).

-That is all. I am absolutely flabbergasted.