I upgraded my survival singleplayer world to 1.14 today (update is amazing, well done!) But when i hit the endermen in at my endermen farm (The EnderMini by gnembon https://youtu.be/ckhe8ws-a4w) the initial "scream" sound from they seemed to stack, which was insanely loud, even at 15% volume. It also caused my tps to spike into the houndreds. There were 250+ sounds at once. I tested this multiple times and it does it consistently. It's only the initial hit though, if you keep killing it seems to be fine.
That was the major issue i found, here are a few others:
Endermen could teleport and stand in the void (Wizards).
(Might be intended?) Endermen could deal damage and knock me back even though they had no vision of me, and i was standing in a 2.5 block high space.
Duplicate of MC-144904.