I created a team simply named "Team" with

/scoreboard teams add Team

I spawned several mobs with Spawn eggs to summon them "naturally"

I added the all entities (including me) to the team "Team" with

/scoreboard teams join Team @e

I walked into the mobs and hit them before and after they were in the Team with me and
created the following list:

Creeper -> doesn't attack you anymore
Skeleton -> doesn't attack you anymore
Spider -> doesn't attack you anymore
Zombie -> doesn't attack you anymore
Slime -> doesn't attack you anymore, but deals damage if touch the Slime
Ghast -> doesn't attack you anymore
Zombie Pigman -> doesn't attack you anymore
Zombie -> doesn't attack you anymore
Enderman -> doesn't get angry at you
Cave Spider -> doesn't attack you anymore
Silverfish -> doesn't attack you anymore
Blaze -> doesn't attack you anymore
Magma Cube -> doesn't attack you anymore, but deals damage if touch the Magma Cube
Witch -> doesn't attack you anymore
Endermite -> doesn't attack you anymore
Guardian -> doesn't attack you anymore
Shulker -> doesn't attack you anymore
Angry Wolf -> isn't at you angry anymore
Zombies wering thorns armor -> You get damage if you hit them

As you can see just two mobs seem to be wrong - and here we come to the bug.
If you run into the Slime or the Magma Cube they still can damage you, even if they don't directly
attack you. (They just jump in random directions.)
Also i don't think the thing with the Thorn Armor was a bug, because its quite logical.

I think the reason could be the same as at
"MC-88099 Slimes with NoAI-Tag cab still damage the Player"

Find mistakes and send them to me to Germany
~froggyman