Editing freebies - false error in Final Details > Categories

This happens frequently. Easy workaround though.
When editing description or other fields for a freebie deal, unable to click the review button to submit the edit. Instead, a a red icon appears by Final Details.

Clicking into Final Details, the below error appears under Categories.

I have to use a workaround so I can submit my edit:

• It won't let me unselect 'Freebies', so I unselect 'Services & Contracts' which is in orange
• I then unselect 'Freebies' which has now turned to orange.
• I can then choose 'Services & Contracts' again.
• I then go to Essentials section - price is empty (despite already entering as £0 during initial deal submission)
• I set price to £0 so that the pop-up appears that says 'your deal has been marked as a freebie' (which ensures the deal correctly appears in both the Services feed and the Freebies feed)
• Now I can Review and submit.