You can lure him to the correct location using Minor Illusion.The trigger location is the floor above the bar, near the Hollyphant Valeria's table, in between the two other tables in the room next to the window.
Picture linked here (also credit for the workaround)
https://www.reddit.com/r/BaldursGat...;utm_term=1&utm_content=share_buttonTips:
1. Make sure your main and Laezel are standing in the area
2. have your main selected when Voss is about to enter the area
3. Be careful around corners as he seems to only investigate the illusion when in line of sight
4. As in the reddit post, you can pickpocket a low-value item if he gets stuck (so he will move to investigate) (you can only do this 3 times)
This worked for me after spamming MI about 20 times - you will not want to do this again though so if youre a save scummer make sure you're happy with the story state!