Some entities don't disappear/still hurt players in peaceful mode.
Does not affect the wither, blaze, ghast, shulker, ender crystal.
Affected entities:
Arrow by skeleton, stray, wither skeleton, illusioner, pillager and piglin shoots.
Spit by llama and trader llama spit out.
Splash potion by witch thrown.
Fangs by evoker summon.
Dragon breath and fire ball by ender dragon shoots.
Pufferfish mob poison.(Fixed)
This issue relates to MC-83017 / MC-91436.