Invulnerable fireballs can now be punched in adventure, unlike in 1.20.4. 

Steps to recreate:

Summon a fireball using this command on version 1.20.4: 

summon fireball ~ ~1 ~ {Invulnerable:1b}

Go into Adventure or Survival mode, and attempt to punch the fireball. You will see that you cannot punch the fireball.

Now, open Minecraft 1.20.5 Release Candidate 1, and summon the fireball using this same command, and attempt to punch it. The fireball will be launched.

What should happen:

The fireball should not be launched, as it was not launched in 1.20.4, and there is no way to make a fireball unpunchable now.