Hi.
You’re right — there is an NPC in that vendor, and he exits the vehicle when the convoy stops.
However, the convoy will not stop if you simply shoot the trader.
Unlike other vehicles, the convoy won’t stop because the vendor cannot detect hits on him (this is a game limitation, not a plugin issue).
In this case, you can shoot the other convoy vehicles, the rear door of this vendor, or the turrets on its roof to make it stop.
If you want, we can remove the NPC from the vendors so this issue won’t happen again. Send me your config and I’ll help you do that.