The discount could have been created with previous settings that didn’t include current restrictions
If the discount was generated before the restrictions were changed in your automation, it won't be affected by the changes. This can happen during the automation when you add the Minimum purchase amount, for example, or restrict the discount to the customer who has placed the order.
The settings of a particular discount code can check in the section Discounts from the Shopify admin panel.
If you need to change the details of a particular discount code, just click it and modify desired parameters.