Hi @Carl Williams ,
How is this a modern site by having classic site navigation in classic mode?
Yes, this is still a modern site.
Why are these different and why are the older site's navigation method not being updated?
This is because you have enabled the Publishing feature on this site. If you don't want to show the classic site navigation, you can disable the Publishing feature. Please follow the steps:
1.Here is a classic site navigation
2.Go to this SharePoint site as a site admin
3.Click Site information >> View all site settings
3.On the Site Settings page, click the Manage site features
4.Find the "SharePoint Server Publishing" feature and click Deactivate >> Deactivate this feature to turn off this feature.
5.Go back to the Site Settings page, click Site collection features
6.Find the "SharePoint Server Publishing Infrastructure" feature and click Deactivate >> Deactivate this feature to turn off this feature.
7.Now, it becomes modern site navigation
Thanks,
Echo Du
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