Hi Ahmet,

Thanks for contacting us here.

1. Please help me check if your individual products have the Sold Individually option enabled.

You can kindly open the Inventory tab of each single product page, check if the Sold Individually option is enabled or not.

The Sold Individually feature is one that allows only 1 offer (1 unit of product with this feature enabled) per customer per order. So only 1 unit of the main item can be added to the cart only. 

You need to turn that off if you would like to offer them in a different quantity in smart bundles.

2. Check the settings in the bundle:

If you enable the Custom Quantity, and put a check in "Use the default quantity as min?", please change the default quantity of your products to 0. Or you can remove the check and enabled Min =0 in Each item's quantity limit.

3. If you are using any external plugin for controlling quantity (Min/Max/Step), it might requires the default quantity to be always 1. You can try disabling that plugin then check again.

Here is our documentation for your needs: https://doc.wpclever.net/woosb/quantity-settings/

Best regards.