Bug with mute

[markino]

No need to press mute immediately. After you send any DTMF on an established call, mute doesn't work anymore. You can send DTMF, then talk for one, five, ten minutes. If now you try to mute, the mute button doesn't work.
The typical scenario for this would be a phone conference: you call a phone number, the service asks you to enter a pin number. You enter the pin and get connected with the other parties on the call. You introduce yourself, speak for a little while, then, in order not to generate too much noise on the conference, press the mute button, and nothing happens.