Sharepoint hub navigation - when adding sublink the "parent" link does not work anymore

When editing the hub navigiation bar, the "parent"-link is still there but it suddenly stops to work. For example in chrome if you hover the mouse over the link no "preview" of the link is showing in the buttom left corner of the window as it does on other links. As soon as i remove the sublink, or move it up a level, the link becomes available again. Is this by design, or is there any workaround?