Shipping being charged for Course products

Hi, I’m using WooCommerce with LearnDash and the Flat Rate Per Country plugin has always worked really well – thanks!

But my client has just noticed that shipping is being charged for her online courses, which are a ‘Course’ product type and should not have any shipping. How can I fix this please? If you use the built-in WooCommerce shipping options then no shipping is charged for courses.

Thank you very much