I have one sample PDF file [1]. I don't know what all the features of the file are, but I think it dynamically takes the date (or just date format) from the system.
When I edit this PDF file (fill form) with Okular which comes from system repositories everything is fine. But when I edit this PDF file (fill form) with Okular which I buit myself as described at https://community.kde.org/Get_Involved/development I get date different format (Mon Aug 20 2018 13:15:02 GMT+0300) instead of original format (11:59:10, 12/03/2018) on the document. And then the PDF form is no longer edited for this or other reasons. [1] https://www.dropbox.com/s/202x1dijd67hdr2/Approved2.pdf?dl=0 -- Anıl Özbek