One user immediately checked out after adding an item to their cart and selecting the amount they want to fund, while intending to do the same for other projects they wanted to fund.
Upon adding other items to their cart, they realized that they could no longer add funding, only reallocate the existing contribution.
We should make this behaviour of the app very explicit to the user, otherwise we risk costing projects money through contributions that we unable to be made.
A warning or click-through tutorial would perhaps be a good solution.