Why does the SMS bubble only appear next to some numbers but not others? This is part of a screenshot showing how my father sees my contact page on iOS 8 on his iPhone:



The four contact details are, in this order:


Phone number (Android device)
Phone number (iPhone)
FaceTime email address
Email address (attached to iMessage)


Why is the SMS bubble not appearing next to one of the phone numbers? Sending and receiving regular texts on that phone number works just fine.

Before jumping on the "because it's not an Apple device" bandwagon, these are two more interesting pieces of information:


Other non-Apple devices display the bubble icon
The phone number on the iPhone device is not using iMessage
How is the android phone number labeled? The SMS bubble shows up if the device is labeled as mobile or iPhone. Otherwise, it is unable to determine if it's a mobile phone that can accept SMS messages or a landline.

The email addresses shows up as iMessage of FaceTime if they are tied to an appropriate Apple ID.