Confusing error when clicking "+" on a cart line that used a voucher

Confusing error when clicking "+" on a cart line that used a voucher: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). What happens: I get an error, but it's the wrong / confusing one. For a require voucher (or hide without voucher ) product I get something like…