The S-ranked bow Rienfleche has an incorrect description in the US localization, claiming it functions like a brave weapon in that it allows the user to attack more often, which is untrue. The EU localization fixed this by giving it the correct description. This error is not present in the Japanese release.
Although it is confirmed in Fire Emblem: Binding Blades that Wolt is the son of Rebecca, she can still die if her health reaches 0, thus causing a paradox. This is likely a development oversight.
In the game exist 4 unused animations for spells. They are actually all from the game's predecessor Sword of Seals, much like the Ballista animations. The animations that exist in the game and are yet unused are of Zephiel's ranged sword attack, Roy's Sword of Seals ranged attack, Fa's Divine Dragon breath, and Iduon's Dark Dragon breath, which is mirrored towards the player due to the weapon being enemy only in it's respective game.