Can't schedule page publishing after changing a content type

When page scheduling is enabled in your SharePoint Online Pages library, a list field that's named PublishStartDate is added to all content types in the Pages library.

If a content type is updated in the Content type gallery from the SharePoint admin center, and if it's published to the site, the PublishStartDate field will no longer be present in the content type. If you make changes to content types from the Content type gallery, this will overwrite any changes that were made to those content types at the site level.

If PublishStartDate isn't present in the content type, you can't schedule page publishing of that content type. If you go to the page and select the edit mode, the Scheduling section will be blank. You expect that the section would contain such elements as the button to turn scheduling on or off and the Publish at this time option.

To restore the ability to schedule pages for the affected content types, follow these steps.

Note You must have administrator privileges to resolve this issue. If you aren't an administrator, contact your Microsoft 365 administrator.

1. Go to your Content type hub. For example, go to https://contoso.sharepoint.com/sites/contentTypeHub.

2. In the site navigation pane, select Pages.

3. In the Pages library, select Scheduling. In the Scheduling panel, change Enable scheduling to On.

4. Navigate to the SharePoint admin center.

5. Under Content services, select Content type gallery.

6. Select the Site Page content type.

7. Select Publish.

8. In Manage Publishing, select Republish, and then select Save.

9. Repeat steps 5 through 8 for any other content types that are affected.

Note It might take 15 minutes or more for the change to appear on all sites.