I'm in the current release of All of Fabric 7 as of 3/30/25. I went to the boss site and broke the block I was supposed to, the event triggered where the blocks break around the boss. However, the boss is both completely inert beyond its idle animation and immune to damage. To note: it can be attacked and has knockback and thorns upon receiving damage. It's healthbar does not drain nor does it engage in any AI behavior such as moving or attacking. Thinking it a one-off event I went to another location and had the same effect occur, this time waiting until it was fully spawned in to attack and breaking the required block with a more conventional pickaxe. I have killed the lich, void blossom, and obsidilith with no issues. Reloading the game does not fix the issue. Leaving the nether and returning does not fix the issue.

It seems the swords was the issue. The Glass Crest Greatsword with some Zenith perks on it was keeping it from hitting the target properly. Not sure why, perhaps due to some AoE effects.