A yt-dlp section download gets the same file name as the whole video

Fact

--download-sections (API: download_ranges) changes what is downloaded but not what the file is called: the default template %(title)s [%(id)s].%(ext)s has no field that varies with the section. Before downloading, yt-dlp checks whether the target file exists and, when it does, reports "has already been downloaded" and returns it. A 15-second clip and the full track therefore satisfy each other: whichever was fetched first comes back for the other request.

Why it matters

Nothing warns. A request for the full album track returns the 15-second clip from an earlier run — with a success status and the right title — and the mistake surfaces only when someone plays the file.

How to apply

Put the range in the name whenever a section is requested, e.g. build %(title)s [%(id)s] [0m05s-0m20s].%(ext)s from the requested start and end, or use the section fields yt-dlp fills in for the output template (%(section_start)s, %(section_end)s). Keep the plain name for the full download so an earlier full file is still reused.