Export of second form is empty if data of forms saved in the same sysfolder

[kanow]

TYPO3: 12.4.33
Powermail: 12.5.1
PHP 8.2

We have two forms. Both of them saving mails in the same sysfolder.
If we are filtering the list with the filter form, we can export the entries afterwards. Everything is fine.
If we are choosing the second form in the filter and trying then to export these list, the export is empty. Just the first line with fieldnames in the excel file. No values. This happens on both xls and csv export.
We need to use "Extended Export Settings" to export data from the second form. It doesn't matter whether I remove a field from the export or add another field to the export.
If I do that, then the export is fine. My selected fields are exported with the values.