The product has been assigned through admin user's My Setup but it does not display in the user's My Setup page in CRM
The user does not have access to the product.
Be sure the user has access to the product.
One method is to adjust the Sharing Settings. Navigate to Setup --> Administration Setup --> Security Controls --> Sharing Settings, select Product Catalog, and then adjust the Sharing Settings accordingly.
Please refer to this guide if needed: Create Sharing Rules
CRM Help Documentation: My Setup Products