Can't say I've had this problem, except for one of the travelling merchants hanging around Novac, who seems to still have the same crap he had, plus the stuff I sold him the last time we met, which is days ago.
I'll see if he resets when I wait a few days elsewhere. All other merchants seem to be resetting ok.
I've had a different merchant issue, though, a number of times: not being given the item I bought, but still having the caps taken from me.
For example, I was at the gun runners, and I decided to bite the bullet and buy Recon Armour. (I was feeling silly running around in a space suit. That thing gets hot in the desert...)
The vendertron had two of them, each under the 50% damage threshold, so I decided to buy both and repair them together.
I buffed up my barter as much as possible, but still shelled out 4000+ caps (I had ~6k at the time).
Then I switched gear, read a repair mag and went to ... oh... why do I only have 1 recon armour?
Did I forget to buy the other? Hmmm... nope, only 2k caps left...
besides I distinctly remember picking both recons, gritting my teeth and clicking Accept...
ok check the vendor... Bugger! There's a recon armour... wait... wtf? it's 100%?
I also had a similar experience with Blake in the crimson caravan - bought something expensive, can't remember what, paid the caps but didn't get the goods.
I noticed it before, but can't remember the merchant as I just shrugged and chalked it up as a one-off glitch at the time.
RPGed it as being ripped off by a shady dealer... even chuckeld (briefly) at being caught be the old 'bait and switch' . "Can I sell you an Eiffel tower, m'sieur?" :deal: :whistling:
So there definitely seems to be something very fishy with the barter mechanism in FONV. I never had any of these problems in FO3. Never got robbed, and they always reset as expected.
I can confirm that sometimes, weapons and armor with an identical level of repair get stacked. You'd say that when you click on repair in this recon armor situation, you would still get to repair the first armor with the second from the repair screen.
As with the merchants not refreshing. With all i've read so far, my conclusion is that the traders only get new inventory after you've gained a couple of levels. That would be logical with what i experienced, since i was getting lots of new stuff from merchants on the low levels, and now, around level 13, its stuck. I will also try saving standing next to a merchant, quiting and restarting and see if that helps.