When crafting a Barkboat, if you have ordinary tree bark and a piece of birchbark in your inventory but the birchbark went into your inventory last, the game will look at the birchbark and try to use that as the "Tree Bark" ingredient, so it won't be able to craft. Easily solved by picking up your actual "tree bark" and putting it back down.
It would be nice if birchbark just wasn't considered "tree bark" for this recipe.