‘Disable Billing Address’ does not support multiple Virtual products

Hi,

I have added two products in the ‘Disable Billing Address fields for certain products’ field. Each product number has been separated by a comma, as shown below:
12, 13

Both items are Virtual products, one of them has been marked as Downloadable. Whenever I add both items to my cart and attempt to checkout, billing address fields are still visible. Strange thing is, if I attempt to checkout with only the Virtual product in my cart the billing address fields are hidden.

Is there something I’m missing? Seeking your advice on this.

Thanks