Bug with skull of guldan

Card costs don’t become cheaper

No bug here. Please search before posting.

Did you happen to introduce Soul Fragments into your deck? If so, it isn’t a bug. Soul Fragments can negate cards effects…
(Ex. Skull , Stiltstepper)

Point your browser over to the wiki, and read on advanced rules here…

https://hearthstone.fandom.com/wiki/Hearthstone_Wiki

  1. The cost is only reduced if the Skull was Outcast (leftmost or rightmost in your hand).
  2. If the Skull draws a card that automatically draws a replacement card, such as a Bomb or Soul Fragment, then the replacement card does not receive the cost reduction, because it wasn’t directly drawn by the Skull.