TYPO3 Core

The import of the attached file (regardless of format) returns success but only imports the page but no content.
The content is a powermail form.

The import message tab lists errors of the form

  0 => 'Possible error: tx_powermail_domain_model_field:1 had no new id assigned to 
      it. This indicates that the record was not added to database during import. 
      Please check changelog!' (175 chars)

(same as those at https://forge.typo3.org/issues/59055).
This error messages originate from sysext/impexp/Classes/Import.php:1018:

A trial to import the file with "Force ALL UIDs values" also created no entries but also did not create the message tab and messages.

So this makes exports/imports basically unusable.