This is not a bug but a flaw that I think Apple could solve, I'm interested in what others think or if there are simple ways around the issue before submitting feedback. If someone associates their iPhone number with iMessage and also enables that number on their iPad, then iMessages sent to that number go to both devices. So far so good. The problem is when the iPhone has no internet but the iPad does. For me this is more likely as the iPad is generally stay at home with wifi on all the time. iPhone goes out and can have no signal occasionally. The iPad will get the iMessage and mark it as delivered on the sender device. This also means the fallback to SMS will not occur for the sender even though the iPhone hasn't got it. iPad may be at home while user out with iPhone so message never seen. Personally I think Apple should be smarter and indicate which devices it has been delivered to, and/or give an option to default to SMS if the iPhone is one of the devices that has not received it. Perhaps there other solutions that are better. It's really useful to have messages received on both devices but not when it's satisfied with it not being delivered to the primary device.