Discarding the Sacrificial Dagger causes you lose 2 Weapon Set Passive Skill Points permanently.

Here's how it happened:
At the sacrificial altar in Aggorat, I took the Sacrificial Dagger and put on the heart, but after that I forgot to pierce the heart and left, defeating Doryani and traveling to Chapter 4.

In chapter 4 at the Clearfell camp, the Sacrificial Dagger was stuck in my backpack and cannot be put into the stash tab. So I threw it away and think of coming back later to finish the quest.

Unfortunately, the Sacrificial Dagger can be discarded, but once I discarded the Sacrificial Dagger, even if I returned to Aggorat, the Sacrificial Dagger would not reappear on the altar, which meant that my character lost 2
Weapon Set Passive Skill Points forever, which is irremediable:
Even if I teamed up with another player and had that other player do the heart stabbing, the quest would still not be completed.

I hope this problem solved soon:
Make the sacrificial dagger return to the altar after it's been discarded / Make the monsters in Utzaal and Aggorat randomly drop sacrificial daggers, or make it so that when you team up, you can backtrack to complete the quest by letting another team member stab the heart, and so on.

same here. i got to act 4 and realized i didnt stab the heart because its in my inventory still lol. i cant get back to the correct area due to it taking me back to the island (act 4 cruel)