Nope, It's happening to me as well...
I just realized it though when I noticed I was broke...Odd because I've been selling everything to him since I started the DLC earlier today...I came into the DLC with 50K caps, I just finished the final quest for it... And also just noticed I didnt have enough money to buy a couple stim packs from him suddenly...
After some research, it's apparent that this guy has been stealing from me...I now have 8 caps and he's sitting on well over 60K...
Ahh well, He now owes me every cap in his inventory, + some...and I cant get them back, or stim packs...
You'd think that by this point in the "DLC process", we'd be past the tedious errors that keep happening...I can understand some errors, but the basic "Buy/sell" function ?
Ahh well, 50 hours of playtime = 8 caps...There went all my savings...lol
I'd be more upset, but ehh...I only picked the game back up cause of the DLC, but now that I beat it there's nothing I really need the money for...