Viber connection problem

Hi Viber Tech team,

I was on a viber call a couple days ago and then suddenly i hear the viber ringtone through my phone from my friend's phone while i was talking to my friend then the call ends.

my friend called me rightaway or automatically called me back the second the call dropped and said that viber started ringing then dropped our call.

Is this situation possible?

thanks.

 

In other words, is it possible to call someone and hear the viber ringtone while on a call with the same person?