Hey @Daniel_Rashi 
- I can’t say for certain what’s causing this, but I do know that this issue has popped up before when it comes to the new Discounts API. This thread here mentions a similar issue: discountAutomaticAppCreate mutation broken in all API versions prior to 2025-04
I’m wondering if the discount that was being used in your function there hadn’t had any classes defined. The classes field was added recently though (in API version 2025-04), so if you were using an earlier version, this could be why the initial classes input field didn’t pop up when the discount itself was created.
If you’re still encountering the issue, could you share an X-Request-ID from an API response header for an example of the error and I can take a look at our logs to see why the issue is popping up if it isn’t your configuration?
Hope this helps - let me know if I can clarify anything on my end here 