Phantom call waiting

[pug29]

Not sure if this is happening to anybody else, but starting yesterday, when I'm on the phone and get another call, I will hear the beep but it won't show me who's calling or give me an option to answer the call. The phone display will change to say 'multiple calls' but that's all it will give me. Any ideas?

iPhone 4s with iOS 6

 

[Chris Bird2]

Yes, my wife is having same problem on her iPhone 5 with iOS 7....

 

[pr1nce]

Yes, my wife is having same problem on her iPhone 5 with iOS 7....

Is this happening often?