Since the recent hotfix, I am taking random damage while just walking about the world for no apparent reason (in peaceful, no enemies or animals nearby):

Example 1:  Just walking on flat ground on grass path blocks near my village base

Example 2:  While ascending a ladder that I've gone up a hundred times before without difficulty.

Example 3:  While placing wood blocks for the foundation of a house (again on flat ground, grass blocks)

Example 4:  Running along my nether hub tunnel, again in peaceful and something I've done a hundred times before without taking damage.