It's my mistake, I actually set to the peaceful mode. The game is running correctly.
Pufferfish nolonger attack mobs in experiments.
How to Reproduce:
create a new world with Update 1.20.
summon some pufferfish in the water.
change player's game mode to survival and close to them.
You can see that pufferfish don't attack player anymore.
I am not able to reproduce this behavior. Are you on Peaceful mode? Please attach a screenshot of this issue occurring with the F3 screen enabled.