CSV export with empty uploaded file rows

Hi there,
I got a strange behaviour during CSV export.
There are multiple file-fields in my form, and when the user uploaded a file, the URL is in the CSV as expected. But when he is not uploaded any, the cell is empty – as expected – but all the cells in that row are empty too.
It seems only the file fields working properly which the last user filled.
(The other field types work fine, it’s happening only with the file uploads, and only in the exported CSV. At the admin side, I see the uploads are working everywhere, but some bug happens during the export.)