Nay... I don't believe it's a bug...
I believe that never applied this "logic".
The reason is the amount of active jewel crafter in game. Since you need only 3 items per hero/merc and with mercs usually equipped with inferior items... There isn't a lot of buyers out there... With this logic then the players would buy from shops for lower prices when to craft a really good jewel is time consuming and costly! The digging for those little shiny rocks is hard and not very efficient... Thus not been able to sell the crafts at high prices would either leave out of business jewel crafters and force them to change job either creating a lack of jewels at shops since the "logic" gives only a little percent for them with a lot of unwanted items at auction...
