The easiest way to test is to make a superflat, place a block, stand on it, then /fill ~-32 3 ~-32 ~32 3 ~32 lava. Then eat chorus fruit.
My best guess as to what's happening is that the teleportation routine's check for liquids is "move the entity to the target, check for intersecting liquids, then teleport it back if any". For some reason that momentary presence in lava doesn't register for an Enderman but it does for a player.
Can confirm.