We are running a small experiment where 0.3% of viewers will see an auto-generated thumbnail, instead of your custom thumbnail. We are not removing the ability to create your custom thumbnail, but we hope to gain insights on auto-generated thumbnails for the future.
@TeamYouTube Did you guys drop this feature or are you still working on it? I just want to see some live area 51 raids but everything is clickbait with custom thumbnails to mislead me.