Endermen randomly attack player about every 1 in 16 throws of an ender pearl.
I was harvesting my chorous fruit farm in the end, using ender pearls to get the seeds. Then, I threw one and hit the side of a very near obsidian pillar, and all the endermen all started swarming me... I threw another one to get into my little enderman thing (I look at the endermen and they come to me) to get away because it is 2 blocks tall, I glitched into a slab, and had 1 heart left, ender pearled again, expecting to die, half a heart. Success! 😃
Feather Falling is truly amazing.
Are you sure this is a bug and not intended behaviour, or that you didn't accidentally make eye contact?
It may have been that you spawned an endermite at your position, making the enderman target the endermite that was at your feet?