This was not a bug. They made it the way it used to be back in 1.2. It's in the notes. Go look. They made it cheep back then on purpose because repair costs were out of hand.
From the patch notes:
"Item sell values and item repair costs now reflect the value of the items and any enhancements attached to them. Previously, items were incorrectly being valued without their enhancements
Sounds like a bug to me.