Why can't I download a QM interaction in audio-video format, even if my role has all the necessary privileges and access to all groups?

If the video retention number of days is lower than the audio retention number of days, the interaction can only be downloaded in audio-only format. Attempting to download an audio-video interaction which has passed the video retention number of days will fail. In such instances audio-only download is possible. This is not a bug in the application, but expected behavior.