Me too - I've also reported this today - it's wild they are charging for this platform when it's so badly checked for bugs. They are not testing it enough at all!!!
Way too many bugs guys... please sort this out. You can't charge for something that doesn't work correctly. Please custom duotone settings have disappeared and there's no way to change duotone to custom colours. PLEASE fix this - this is needed for designers!!!
On IOS you can change the two colours for Duetone effect on images. But on the Desktop version it doesn't show you the two colours to change. It only changes one of the colours.
I'm also having the same issue. I can no longer customize duotone colors. I really need this feature for my job tasks. Please let us know if there's a work-around to change colors in Adobe Express.