I've been doing turn ins a bit more than usual now that it's such a big jump between levels and I want lots of seals to buy survival guides for DoL :). I had a turn in for carpenter today that was a bit different from the others I've had before. When I opened the "Timers" menu to see what the items for the day were, the Carpenter item was a Mythril Cavalry Bow, with a yellow/gold star next to it. When I went to actually turn the item in, the gold star was there on that menu as well, and the text in the window was red. It's the first and only time I've seen something like this.
I asked in FC chat, and though one person had seen something similar at a lower level, nobody knew what it meant.