Delivery Note group same items

Today I tried to create a Delivery Note with the same Items from different Warehouses. Since we would like to display it as a single row on the DN, I ticked the ‘Group same items’ checkbox. This works fine, the Items are grouped and quantities are calculated correctly. However, just the Serial No’s for the first Item row are shown on the DN. Are we doing something wrong or is it a bug?

Thanks!