I have a similar issue, since iOS10, except the call appears but it´s silent. It's silent when it's a phone call, but it rings if it's a FaceTime call (audio or video). One more thing... LOL if I missed the call, if it's a FaceTime one I have the notification on the lockscreen + the 1 red thing on FaceTime app. But if it's phone call, nothing... If I missed it, I have nothing to know. I tried to restore the iPad as new, etc nothing... I even restored all my devices as new during one weekend, still the same. The mac shows everything fine, the Apple Watch too, but for some reason the iPad has trouble. Is it an iOS 10 bug? Before it working fine.