Joining game #5097070 on oregon. In the game I had played 3 charms. 2 I used for extra buy while I used the 3rd for extra card. I had 13 money and bought 1 Province and 1 Duchy. The Duchy should give me an extra 5er card.
Charm gives you the "differently named card with the same cost" only for the next buy
. You bought the Province first, Duchy second on turn 14, so the game worked correctly. If you bought them in reverse order, you could have done what you intended.
I should also be able to get to of the same cards with 2 charms. Having 2 cards in play for extra card I bought a charm and then chose a Market. For the second charm I couldn't get a market or charm anymore.
I guess this is about turn 13, where according to the log you bought a Market and used 2 Charms to gain a Charm and a Count. I tried and I could get 2 Counts or 2 Charms at that point. Maybe you simply forgot to click on the Charms pile to buy a Charm (you had just clicked on 2 Charms in your hand to play them). In that case, when you clicked on the Market and thought you were gaining it via Charm#1, you where actually buying it. So in this case the game correctly disallowed you to gain another copy of it via the Charms.