scrollSpy: Can not find header element

[TwiggyBuffalo]

Description

scrollSpy's listener floods the console with the following error on https://babeljs.io/docs/en/v7-migration I suspect this link is to blame. Heading over to the deprecated-yearly-presets page, it throws the same error with an id of undefined.

Screenshot

[babel-bot]

Hey @TwiggyBuffalo! We really appreciate you taking the time to report an issue. The collaborators on this project attempt to help as many people as possible, but we're a limited number of volunteers, so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack community that typically always has someone willing to help. You can sign-up here for an invite.

[JLHwung]

I can't reproduce this issue after upgrading to docusaurus 2. Feel free to reopen it if there are similar issues.