FCP loses second audio track on import I have mp4 files with two stereo audio tracks, one with voice, and the other with game sounds. Unfortunately, when I import into Final Cut Pro, and then expand audio components, I only get the first (voice) track. Everything I can find claims that I should be seeing both tracks. What am I doing wrong here? Is there an import switch not set properly?
Make sure to activate “Separate mono and group stereo audio “ and deactivate “Remove silent channels” in the import window. 
Maybe consider to check the files with VLC or Audacity to make sure both channels are present. You could export just the audio tracks and import them separately as well.