[llacb47]

https://support.google.com/youtube/thread/61967856?hl=en

    If you have contributions currently saved as drafts, these will be available for the next 60 days (until Sept 28 2020), and you have until then to publish them before they’re removed. Any already published contributions (titles, descriptions, captions, etc) will continue to show up on videos and can be managed by Creators in YouTube Studio.

[zaarn]

IIRC this was basically what they said when annotations become unavailable to new videos. They're completely gone now, so probably a year or so until community contributions are completely wiped.

[pwinnski]

Ah, okay, thanks for explaining!