Repository: youtube-dl
Issue: [Pluralsight] the list extracted by youtube-dl is different from the real course list
Labels: account-needed

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## Checklist

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Carefully read and work through this check list in order to prevent the most common mistakes and misuse of youtube-dl:
- First of, make sure you are using the latest version of youtube-dl. Run `youtube-dl --version` and ensure your version is 2021.04.26. If it's not, see https://yt-dl.org/update on how to update. Issues with outdated version will be REJECTED.
- Make sure that all provided video/audio/playlist URLs (if any) are alive and playable in a browser.
- Make sure that all URLs and arguments with special characters are properly quoted or escaped as explained in http://yt-dl.org/escape.
- Search the bugtracker for similar issues: http://yt-dl.org/search-issues. DO NOT post duplicates.
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- Finally, put x into all relevant boxes (like this [x])
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- [x] I'm reporting a broken site support issue
- [x ] I've verified that I'm running youtube-dl version **2021.04.26**
- [x ] I've checked that all provided URLs are alive and playable in a browser
- [x ] I've checked that all URLs and arguments with special characters are properly quoted or escaped
- [x ] I've searched the bugtracker for similar bug reports including closed ones
- [x ] I've read bugs section in FAQ


## Verbose log

<!--
Provide the complete verbose output of youtube-dl that clearly demonstrates the problem.
Add the `-v` flag to your command line you run youtube-dl with (`youtube-dl -v <your command line>`), copy the WHOLE output and insert it below. It should look similar to this:
 [debug] System config: []
 [debug] User config: []
 [debug] Command-line args: [u'-v', u'http://www.youtube.com/watch?v=BaW_jenozKcj']
 [debug] Encodings: locale cp1251, fs mbcs, out cp866, pref cp1251
 [debug] youtube-dl version 2021.04.26
 [debug] Python version 2.7.11 - Windows-2003Server-5.2.3790-SP2
 [debug] exe versions: ffmpeg N-75573-g1d0487f, ffprobe N-75573-g1d0487f, rtmpdump 2.4
 [debug] Proxy map: {}
 <more lines>
-->

```
$ youtube-dl --version
2021.04.26
USER:01-Layer 2 Switching and VLANs in Junos OS USER$ youtube-dl      --flat-playlist  -v
[debug] System config: []
[debug] User config: ['-u', 'PRIVATE', '-p', 'PRIVATE', '-i', '-c', '--no-warnings', '--console-title', '--batch-file=batch-file.txt', '--max-sleep-interval', '150', '--min-sleep-interval', '120', '-o', '%(playlist_title)s/%(chapter_number)s - %(chapter)s/%(playlist_index)s-%(title)s.%(ext)s', '-f', 'bestvideo[height<=720]+bestaudio/best[height<=720]/worst']
[debug] Custom config: []
[debug] Command-line args: ['--flat-playlist', '-v']
[debug] Batch file urls: ['https://app.pluralsight.com/library/courses/juniper-networks-jncis-ent-jn0-343-layer-2-switching-vlans']
[debug] Encodings: locale UTF-8, fs utf-8, out utf-8, pref UTF-8
[debug] youtube-dl version 2021.04.26
[debug] Python version 3.9.4 (CPython) - macOS-11.2.3-x86_64-i386-64bit
[debug] exe versions: none
[debug] Proxy map: {}
[pluralsight:course] juniper-networks-jncis-ent-jn0-343-layer-2-switching-vlans: Downloading JSON metadata
[download] Downloading playlist: Layer 2 Switching and VLANs in Junos OS
[pluralsight:course] playlist Layer 2 Switching and VLANs in Junos OS: Collected 29 video ids (downloading 29 of them)
[download] Downloading video 1 of 29
[download] Downloading video 2 of 29
[download] Downloading video 3 of 29
[download] Downloading video 4 of 29
[download] Downloading video 5 of 29
[download] Downloading video 6 of 29
[download] Downloading video 7 of 29
[download] Downloading video 8 of 29
[download] Downloading video 9 of 29
[download] Downloading video 10 of 29
[download] Downloading video 11 of 29
[download] Downloading video 12 of 29
[download] Downloading video 13 of 29
[download] Downloading video 14 of 29
[download] Downloading video 15 of 29
[download] Downloading video 16 of 29
[download] Downloading video 17 of 29
[download] Downloading video 18 of 29
[download] Downloading video 19 of 29
[download] Downloading video 20 of 29
[download] Downloading video 21 of 29
[download] Downloading video 22 of 29
[download] Downloading video 23 of 29
[download] Downloading video 24 of 29
[download] Downloading video 25 of 29
[download] Downloading video 26 of 29
[download] Downloading video 27 of 29
[download] Downloading video 28 of 29
[download] Downloading video 29 of 29
[download] Finished downloading playlist: Layer 2 Switching and VLANs in Junos OS
```


## Description

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the course tables of content are different with the flat-playlist and downloaded file with youtube-dl.
if you look at the original course here (in below) there is 34 files but the flat-playlist shows only 29 files. 
https://app.pluralsight.com/library/courses/juniper-networks-jncis-ent-jn0-343-layer-2-switching-vlans/table-of-contents