So I've discovered the Sink AI vendor no longer gives me caps during sales, but it will take my items. I was just wondering if there was some sort of workaround for this problem, or if Bethesda/Obsidian are aware of this issue and have any plans for a patch for this and other issues present in this DLC. I have already tried waiting several days for the caps/stock to reset, but nothing changes.
Thank you.

I heard this begins after selling back pre-war money. So try buying up the prewar money in the vendors Inventory.

Don't believe I sold him anywhere pre-war money. But I will check, thanks for your help.