@TeamYouTube Can you PLEASE help me with a very nasty bug on YouTube? I sent feedback 2 times already during the past days, no response, nothing fixed. It is just a small thing to fix, so please help me to be able to do my work again. Thanks in advance!
... generated the error "Video uploaded to a different channel cannot be added to a series playlist.". But it WAS the same channel. Finally the problem could be solved by unchecking "Set as official series for this playlist" from the playlist settings. I found this solution...