POE2 BUG stuck in Trial of Corruption

I got stuck in the quest "Trial of corruption".

I've searched the forum. Most of ppl solved the issue by below:
1. Travel to traitor's passage.
2. Move to front of Caravan
3. Then, they'll be able to use the horn.

However, my issue is different. I've already use the horn but I literally got stucked in the mission somehow. I've tried everything I could. (Start new instance, run different area maps, tried complete normal ACT)

Please also see the screen shot as below: https://imgur.com/8r9JRWQ

I've already invested a lot of time in the character. Don't want to restart another one.

MY IGN: HUGOSHOT

same here, very annoying...