I have a strange error when using an Active class to send DTMF's during a voice call.
I initiate a voice call ,
When the call is Connected ,
I send several DTMF's :

The error occures only if during the DTMF's ,
the call is hanged up by the destination device.
The error:
The "disconnected" message appears and it just won't go off , only restarting the device will take it off...

This will not happen if I will hang up the call from the device which initiated the call.
debugging of the events shows that both hang up's result in the same status event :
the only thing I do after this event is iCall.Close(); (ofcourse I tried to see if deleting this line solves the error but it doesnt)

Do you have any idea what could cause this error ,
and why it happenes only when the destination device hangs up the call ?
Any idea how to solve it ?

Thank you & Enjoy your weekend