Act 5, bug final letter cannot complete

I took the final letter. When I return to the caravan, I cannot complete the quest even though I have the letter
ขุดครั้งสุดท้าย เมื่อ 20 เม.ย. 2025 09:41:59
I have the same issue! I can't complete it because the NPC doesn't give the option to do so... Now I stopped playing because I'm frustrated with this.
What npc do you talk to? Give screenshot of you talking to that npc
Thank you for the reply. I was trying to give it straight to Shambrin, but you gotta talk to Zarka before doing it, now my issue is solved!

รายงานโพสต์

รายงานบัญชี:

ประเภทรายงาน

ข้อมูลเพิ่มเติม