I was importing this video https://www.youtube.com/watch?v=IADZtE2-Aws into my youtube account, famous tracking shot from Wings 1927, and at the copyright determination step Youtube told me it was under copyright but the owner allows it to be shown on Youtube.

Which is incorrect - it entered public domain in 2023.

Makes me wonder if there is some metadata in this file that is newer than the film and that is what is copyrighted, or is it that the copyright was claimed on years past and Youtube neglected to check when that claim was going to run out?

How does one let them know that the copyright has run out?

There is a discussion on Hacker News, but feel free to comment here as well.