Created attachment 105881 [details]
PPD used for creating print queue
Libreoffice sends A4 even though A4.duplex is selected in the Libreoffice print dialog. Since there is a constraint between A4 and Duplex=Long or Short Edge and looks like because of that Libreoffice changes Duplex option from Long/short Edge to OFF as well. Just to prove what I said, I captured the application output file (d00009-001.pdf) and its corresponding control file(c00009), I can see that below options are passed on to cups in c00009 file.
Please find c00009, d00009-001.pdf files in below bug report.
The ppd used for creating the print queue is attached in this Bug report.
Created attachment 105882 [details]
IPP request file passed on to Cups while printing
I believe this is a duplicate of bug #60428.
*** This bug has been marked as a duplicate of bug 60428 ***