It seems that whenever you eat a chorus fruit and it teleports you to a lower elevation, it applies fall damage to all blocks traveled down from place of origin(consumption).
For example, that happened to me a lot, if you're on a end city tower and eat a chorus, you'll be teleported to ground level, no damage there, but if you jump and land, it applies all the blocks traveled from tower to ground. However, if you place water on your feet after teleporting, then jump, the fall damage is nullified.
Another example is, when flying with an elytra, eating a chorus fruit will send you to ground, but this time, without giving you the chance to place water, instantly applying all the traveled blocks of damage, possibly and most likely being fatal.
Lost a mending elytra on the last example, deleted world from anger afterwards. Sad.