Test using WordPress Playground

The changes in this pull request can previewed and tested using a WordPress Playground instance.

WordPress Playground is an experimental project that creates a full WordPress instance entirely within the browser.

Some things to be aware of

• The Plugin and Theme Directories cannot be accessed within Playground.
• All changes will be lost when closing a tab with a Playground instance.
• All changes will be lost when refreshing the page.
• A fresh instance is created each time the link below is clicked.
• Every time this pull request is updated, a new ZIP file containing all changes is created. If changes are not reflected in the Playground instance,
  it's possible that the most recent build failed, or has not completed. Check the list of workflow runs to be sure.

For more details about these limitations and more, check out the Limitations page in the WordPress Playground documentation.

Test this pull request with WordPress Playground.

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

Core Committers: Use this line as a base for the props when committing in SVN:

Props abcd95, circlecube.

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

I reproduced this issue by creating a few pages and changing the publish date, and then saving as a draft (or scheduled). I indicated in the page title when the publish date is and when it was last modified. Here is the issue reproduced on core in latest on playground (not the PR code):

The date this was created is 8/26, so yesterday refers to 8/25, but the post was just edited.

Then I opened the PR "Test in Playground" and created the same pages for this screenshot to show the changes to fix the issue. The posts now display the last modified date in favor of the publish date (even though they are not published):

This may be by design to show the "publish" data for draft posts, but if so, the label is incorrect. Not sure the best UX when a post has a publish date set, but the last modified date is different - should it show last modified or the desired publish date? Either way, though, either the label or the date data needs to be updated, since the label does not match the data. Either we need to update the date data, as this PR does to match the label of "Last Modified" or the label should be updated.

I think the last modified data is more relevant than the publish data since the page is not published yet (so publish date is irrelevant).