facetime and IOs updates

We have been using FaceTime for over a year now between our iphones and ipads without any problems. However since the iOS 11 was issued, we begun to have problems and now with every new update, our FaceTime settings get messed up.......

We have a total of 6 facetime users, everybody is using Apple device, some are different model, some are different platforms - iphones and ipads. However, after every iOS update, FaceTime calling directory gets out of order. When I try to call my mom - then my wife answers, when I try to call my son - my daughter's iphone rings..... It is extremely frustrating and annoying. So we all have to get on phones and everybody change the FaceTime settings, it works again until next iOS 11 is issued and the circus starts again...... Is it only our problem, or are there any other users who have been experiencing it ? what is the permanent solution for it ?