Reported: The Cheating Card window over a targeted monster only ever shows the bomb or a chest, never the other cards, and the card visuals sometimes break.
Found: The bomb is the Blank card. When a monster appears, the server sends the first card in the list as its card, and that card is Blank, so every monster shows the bomb until a Monster Cheating Card is used on it.
Our card system is a stand-in: a monster only gets a real card after a card is used on it, and matching your card to the monster's gives no bonus yet. The game's own guide describes every monster carrying a card from the start and a bonus for a match, and that part is not built.
Planned fix: Rebuild the cards the way the guide describes: every monster except pit bosses carries a card from its spawn, and a matching card pays its bonus. Nothing more is needed from you for now.