As I recently found out that I somehow managed to miss the Dud on BF19, and that since Duds actually lead up to a really nice item if you get them all, I recommend that, in the map notes that the Duds are on, you specifically point out the Duds existing on that particular battlefield. I noticed that this is not a problem with BF16, as Sturm has mentioned that both Duds there are obtainable there (obviously), but for the second BF with a Dud (BF19), an enemy is standing on the spot with the Dud, and Sturm makes no mention of the Dud being there. To further prove my point that the Dud in BF19 is easy to miss because Sturm doesn't point it out is that for the diagram in BF19-2, the spot with the Dud is also in range of the cannon, and thus the diagram puts emphasis on the cannon range, as opposed to the item colorization, thus giving the illusion that an item really doesn't exist on that spot.

And thus, that would be my suggestion: To make some effort at pointing out the Duds in textual context, not just some little icon you have to scroll over for the Battlefields the Duds are on. Those battlefields would be 16, 19, 22, 35, and 38. There are two Duds on 16 and 38, and the one on 35 requires either Horse or Dragon movement.

Open to discussion~