This has already been addressed for audio|video shortcodes, but also needs to be the case for playlists. When loading a playlist from a DOM cache or via AJAX, and when the sources match those already pre-loaded, the browser will sometimes donkey-punch the HTTP request for the first cached track selected.
Set `preload="none"` for the empty `<audio|video>` tag for playlists.
See commits related to #26779.
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