When you visit the node add form as a user who can edit the authoring information, you'll find that the "Authored on" field contains an actual date and time (when the form was generated). This is a departure from prior versions of Drupal, where the field would start out empty so that the form submission time was used.
Now you would have to remember to manually wipe out that field for the correct time to be saved.
Needs work
10.1 ✨
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
This is still the case, but the patch to remove the default value breaks the node add form with:
InvalidArgumentException: The timestamp must be numeric. in Drupal\Component\Datetime\DateTimePlus::createFromTimestamp() (line 201 of core/lib/Drupal/Component/Datetime/DateTimePlus.php).