[POE2][Act 2] Quest "A Theft of Ivory" – Mastodon Tusks not dropping, progression blocked

Hello,

I am completely stuck in Act 2 due to a quest progression bug.

Quest: "A Theft of Ivory"
Objective: Retrieve the Mastodon Tusks

Problem:
I have killed the Mastodon boss multiple times (4+), always in fresh instances.
The Mastodon Tusks never drop.
Because of this, I cannot reconstruct the Horn of the Vastiri.
Without the horn, I cannot reach the Yamanra encounter.
Act 2 progression is fully blocked on this character.

Additional information:
- Fresh instance created every attempt
- Boss kill confirmed
- No quest item drops
- This worked correctly on a previous character
- This character is permanently stuck

Please investigate this quest state bug or reset the quest progression.

Thank you.