When attempting to insert an audio (mp3) file via the Media Manager ("Insert/Edit Media" button) the "Insert" button will not work unless a width and height is input manually. This was never required before, and audio files should not require a custom width/height.

I have only observed this on audio files; video files work normally, as do images and links.

I'd rather not install a Beta version on a client's production site. Does this mean it's a known issue that should be resolved in a later stable release?