One contact, two iMessage threads?
I've got one contact on my iPhone that has a mobile phone number and an email address, both of which are associated with her own iMessage account. When I send her an iMessage, if I choose the mobile phone number, my iMessage goes into one thread; and if I select the email then the iMessage goes into a different thread. Both are iMessage, neither are SMS. Is this the way iMessage is supposed to work? It sure is darned annoying.
iPhone 6, iOS 10.2.1, null