I've fixed this and uploaded a new version (note the _ at the end of the url to ensure CDNs are delivering the correct version):

https://files.kde.org/akademy/2020/akademy2020-234-adventures_in_open_source_development_.mp4

For youtube, I've unlisted the old version (not deleted). I've published the new one, but did so silently so that we didn't announce via the subscribers feed.

On conf.tube, I've done similar:

https://conf.tube/videos/watch/b7126318-1656-4024-b8dd-ea37751ca1fa

Playlists on both platforms have been updated.