Board Thread:LOC General Discussion/@comment-6053607-20130513181118/@comment-5706972-20130513185847

I would be willing to bet the cards that 'disappear' like that are one of two things, either:

a. they are unskilled commons, and you are trying to enhance a maxed card

- A card can be skilled, even when already fully enhanced, but obviously unskilled cards will not help you, so the system 'filters' them out

b. The card is already itself a skill 10

- If you are looking to 'Change card to enhance' - you are obviously not planning to enhance a card already at skill level 10 - so again, the system 'filters' them out.