Not a bug, all MVP cards and some mini-boss cards are now untradeable, they can only be traded through the help of a GM, through the use of the support ticket system.
Any carded MVP cards/mini-boss cards can still be traded, for example, a DR FAW can be traded but a DR card can not.
This was instituted early March.
http://forums.warppo...th-maintenance/
Due to widespread RMT issue that the development team has not yet been able to address, unfortunately we have to temporarily make MVP cards as well as Ghostring, Deviling and Maya Purple cards untradable. This will not affect cards that have already been put into equipment. The GM Team can assist with moving these loose mvp cards around.