Well I know that while you can unlock them with just 1 cube, you have to have a certain number of cubes to actually collect the recolor (the number is in the bottom left of that first picture). If you already gotten that many and it's still not working then I don't know.
I just found out it's a known bug that it relocks after exiting and the devs are trying to fix it now! Thank you for the help tho!













