This stuff is indeed quite confusing, as the "detailed" card info was not designed into deckbox at start, I added it later, and then even way later I added the "detailed cards" support to decks in the form of "built decks". It's a bit clunky, and it confuses me too sometimes, even if I wrote the damn thing. At some point I need to clean this whole UI and interaction.
For deckbox to try to match your decks to your inventory 2 things have to be checked actually:
- the "is built" flag, which signifies that you actually intend to use this deck and either have or want the cards (as opposed to just some idea for a deck, or a deck that is actually a listing of some other types of cards, or as a reminder of something you once played, or a friend's deck etc etc)
- the "Edition/Price Match" dropdown in the deck, where you can leave it on default which does not try to guess any card details at all, or "my inventory" which will try to match the cards in your inventory to the ones in the deck
Finally, if this detection does not work, the only way you can get it to specifically set printings/language/condition/flags to cards on decks is to manually and explicitly set this information in the deck listing on each card via the dropdown in the "edition" column.