Created attachment 91931 [details]
File having Mirrored Margin
<w:mirrorMargins/> is not preserved in RT
Vinaya Mandke committed a patch related to this issue.
It has been pushed to "master":
fdo#73541 "Page Margins : Mirrored" was not preserved on export to DOCX
The patch should be included in the daily builds available at
http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
Affected users are encouraged to test the fix and report feedback.