Ahmed,
I experienced the same thing with either my digibeta deck or my betasp deck when capturing with my Kona 3. I found that if you disengage the Log and Capture command (command F8) after capturing video and audio, the audio was restored immediately. Without putting the window away, I couldn’t hear anything coming from the viewer or canvas. Don’t know if that’s the way its supposed to work but it keeps the workflow going.
Mark