When in lava, leaving the world and then rejoining the world teleports the player outside of the lava. This location varies based on my testing and the video recorded. At one time, I was teleported right outside the lava, on the smooth stone blocks surrounding it. This was tested on a flat world, originally created in Creative with Cheats enabled, but the default gamemode then changed to Survival. Coordinates are included in the video attached.

This may or may not be intentional, but I do not think this should be happening as it is a cheaty way to get yourself out of lava.

Note: I originated wanted to recreate a bug my friend experienced where he was in lava within a cave, left and rejoined, and got teleported to a space above the cave, specifically a room we had mined out. My friend experienced this on a world with Cheats disabled. This was what the blocks above the lava was for, but I was unable to recreate the bug experienced by my friend as I experienced this bug instead.