Doesn't work "autonumber" increasing in OUTPUT TEMPLATE

[Lirk88]

Checklist

• I'm reporting a broken site support issue
• I've verified that I'm running youtube-dl version 2020.07.28
• I've checked that all provided URLs are alive and playable in a browser
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched the bugtracker for similar bug reports including closed ones
• I've read bugs section in FAQ

Verbose log

youtube-dl -v https://www.youtube.com/watch?v=oJ2LLnAQGHI -o "%(autonumber)s-%(title)s-%(id)s.%(ext)s"
[debug] System config: []
[debug] User config: ['--no-check-certificate', '-f', 'bestvideo[height<=720][height>=360][ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best', '-o', '%(title)s-%(id)s.%(ext)s']
[debug] Custom config: []
[debug] Command-line args: ['-v', 'https://www.youtube.com/watch?v=oJ2LLnAQGHI', '-o', '%(autonumber)s-%(title)s-%(id)s.%(ext)s']
[debug] Encodings: locale cp1251, fs mbcs, out cp1251, pref cp1251
[debug] youtube-dl version 2020.07.28
[debug] Python version 3.4.4 (CPython) - Windows-7-6.1.7601-SP1
[debug] exe versions: ffmpeg git-2020-06-28-4cfcfb3, ffprobe git-2020-06-28-4cfcfb3, phantomjs 2.1.1, rtmpdump 2.4
[debug] Proxy map: {}
[youtube] oJ2LLnAQGHI: Downloading webpage
[debug] Invoking downloader on '...'
[download] Destination: 00001-Milk Inc. - Oceans (Live @ Vrt Summer 1999)-oJ2LLnAQGHI.f135.mp4
[download] 0.0% of 21.48MiB at 333.33KiB/s ETA 01:05
[download] 0.0% of 21.48MiB at 750.01KiB/s ETA 00:29
[download] 0.0% of 21.48MiB at 1.71MiB/s ETA 00:15
[download] 0.1% of 21.48MiB at 2.44MiB/s ETA 00:08
[download] 0.1% of 21.48MiB at 3.78MiB/s ETA 00:05
[download] 0.3% of 21.48MiB at 4.39MiB/s ETA 00:04
[download] 0.6% of 21.48MiB at 5.91MiB/s ETA 00:03
[download] 1.2% of 21.48MiB at 5.79MiB/s ETA 00:03
[download] 2.3% of 21.48MiB at 8.60MiB/s ETA 00:02
[download] 4.7% of 21.48MiB at 9.16MiB/s ETA 00:02
[download] 9.3% of 21.48MiB at 9.66MiB/s ETA 00:02
[download] 18.6% of 21.48MiB at 10.18MiB/s ETA 00:01
[download] 37.2% of 21.48MiB at 10.47MiB/s ETA 00:01
[download] 44.5% of 21.48MiB at 10.60MiB/s ETA 00:01
[download] 44.5% of 21.48MiB at 499.98KiB/s ETA 00:24
[download] 44.5% of 21.48MiB at 1.46MiB/s ETA 00:08
[download] 44.5% of 21.48MiB at 3.42MiB/s ETA 00:03
[download] 44.5% of 21.48MiB at 4.88MiB/s ETA 00:02
[download] 44.6% of 21.48MiB at 3.78MiB/s ETA 00:03
[download] 44.8% of 21.48MiB at 4.73MiB/s ETA 00:02
[download] 45.1% of 21.48MiB at 5.91MiB/s ETA 00:01
[download] 45.6% of 21.48MiB at 7.11MiB/s ETA 00:01
[download] 46.8% of 21.48MiB at 7.80MiB/s ETA 00:01
[download] 49.1% of 21.48MiB at 7.51MiB/s ETA 00:01
[download] 53.8% of 21.48MiB at 7.81MiB/s ETA 00:01
[download] 63.1% of 21.48MiB at 7.95MiB/s ETA 00:00
[download] 81.7% of 21.48MiB at 8.10MiB/s ETA 00:00
[download] 89.4% of 21.48MiB at 8.15MiB/s ETA 00:00
[download] 89.4% of 21.48MiB at 999.83KiB/s ETA 00:02
[download] 89.4% of 21.48MiB at 1.46MiB/s ETA 00:01
[download] 89.5% of 21.48MiB at 3.42MiB/s ETA 00:00
[download] 89.5% of 21.48MiB at 7.32MiB/s ETA 00:00
[download] 89.6% of 21.48MiB at 4.32MiB/s ETA 00:00
[download] 89.7% of 21.48MiB at 4.73MiB/s ETA 00:00
[download] 90.0% of 21.48MiB at 6.53MiB/s ETA 00:00
[download] 90.6% of 21.48MiB at 7.78MiB/s ETA 00:00
[download] 91.8% of 21.48MiB at 7.45MiB/s ETA 00:00
[download] 94.1% of 21.48MiB at 8.76MiB/s ETA 00:00
[download] 98.7% of 21.48MiB at 9.66MiB/s ETA 00:00
[download] 100.0% of 21.48MiB at 9.79MiB/s ETA 00:00
[download] 100% of 21.48MiB in 00:02
[debug] Invoking downloader on '...'
[download] Destination: 00001-Milk Inc. - Oceans (Live @ Vrt Summer 1999)-oJ2LLnAQGHI.f140.m4a
[download] 0.0% of 3.06MiB at 333.23KiB/s ETA 00:09
[download] 0.1% of 3.06MiB at 749.83KiB/s ETA 00:04
[download] 0.2% of 3.06MiB at 1.71MiB/s ETA 00:01
[download] 0.5% of 3.06MiB at 2.44MiB/s ETA 00:01
[download] 1.0% of 3.06MiB at 3.36MiB/s ETA 00:00
[download] 2.0% of 3.06MiB at 4.73MiB/s ETA 00:00
[download] 4.0% of 3.06MiB at 6.20MiB/s ETA 00:00
[download] 8.1% of 3.06MiB at 6.92MiB/s ETA 00:00
[download] 16.3% of 3.06MiB at 8.91MiB/s ETA 00:00
[download] 32.6% of 3.06MiB at 8.76MiB/s ETA 00:00
[download] 65.2% of 3.06MiB at 9.70MiB/s ETA 00:00
[download] 100.0% of 3.06MiB at 10.11MiB/s ETA 00:00
[download] 100% of 3.06MiB in 00:00
[ffmpeg] Merging formats into "00001-Milk Inc. - Oceans (Live @ Vrt Summer 1999)-oJ2LLnAQGHI.mp4"
[debug] ffmpeg command line: ffmpeg -y -loglevel "repeat+info" -i "file:00001-Milk Inc. - Oceans (Live @ Vrt Summer 1999)-oJ2LLnAQGHI.f135.mp4" -i "file:00001-Milk Inc. - Oceans (Live @ Vrt Summer 1999)-oJ2LLnAQGHI.f140.m4a" -c copy -map "0✌️0" -map "1🅰️0" "file:00001-Milk Inc. - Oceans (Live @ Vrt Summer 1999)-oJ2LLnAQGHI.temp.mp4"
Deleting original file 00001-Milk Inc. - Oceans (Live @ Vrt Summer 1999)-oJ2LLnAQGHI.f135.mp4 (pass -k to keep)
Deleting original file 00001-Milk Inc. - Oceans (Live @ Vrt Summer 1999)-oJ2LLnAQGHI.f140.m4a (pass -k to keep)

youtube-dl -v https://www.youtube.com/watch?v=oJ2LLnAQGHI -o "%(autonumber)s-%(title)s-%(id)s.%(ext)s"
[debug] System config: []
[debug] User config: ['--no-check-certificate', '-f', 'bestvideo[height<=720][height>=360][ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best', '-o', '%(title)s-%(id)s.%(ext)s']
[debug] Custom config: []
[debug] Command-line args: ['-v', 'https://www.youtube.com/watch?v=oJ2LLnAQGHI', '-o', '%(autonumber)s-%(title)s-%(id)s.%(ext)s']
[debug] Encodings: locale cp1251, fs mbcs, out cp1251, pref cp1251
[debug] youtube-dl version 2020.07.28
[debug] Python version 3.4.4 (CPython) - Windows-7-6.1.7601-SP1
[debug] exe versions: ffmpeg git-2020-06-28-4cfcfb3, ffprobe git-2020-06-28-4cfcfb3, phantomjs 2.1.1, rtmpdump 2.4
[debug] Proxy map: {}
[youtube] oJ2LLnAQGHI: Downloading webpage
[download] 00001-Milk Inc. - Oceans (Live @ Vrt Summer 1999)-oJ2LLnAQGHI.mp4 has already been downloaded and merged

Description

"Autonumber" is added to the first video, but not to subsequent videos.

[dstftw]

It's not supposed to preserve across different runs.