I am using iOS 10. I created a collection, then tapped "Invite/Share," then "Invite a friend," then "Invite from Contacts." I tap my desired contact, but other than highlighting that contact with a grey bar, nothing happens. I cannot figure out how to close the contacts interface, neither in a way that actually invites the contact, nor by clicking "cancel." However, I seem to be able to invite via email and share with friends via text. If you need any more detail from me on this bug, please let me know.