Can't complete quest "The Lost Flute"

Bug Report 2594245294

Update: It seems there's an option for the reward as a dialogue option. The problem is when talking to Una, the dialogue is scrolled to the bottom by default so the option is hidden until you scroll up.

When handing in this quest I accidentally used the X button rather than square to try and take the reward. This seems to have picked it up, but then placed it back into the reward selection area and closed the dialogue box, leaving me without the reward.

The problem is, when I started hand in, it took the quest item from my inventory but the quest doesn't register as finished in my quest log, telling me to "Talk to Una for a reward" however without the flute in my inventory, she doesn't offer a reward, so I have a quest I can't complete.