files saved as "ext(s)" and "ext(s).description"

[kileytoo]

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Description of your issue, suggested solution and other information

I am having issues with filenames. If I use --id, it works as expected. If I use -o "%(id)s.%(ext)s", which should give the same result, the file is saved as "ext(s)" instead--in other words, special sequences are not recognized. I am running the Windows executable that includes Python just downloaded from https://rg3.github.io/youtube-dl/