How to reproduce:
* Open Writer
* Click on the header of the document -> a blue menu will pop up
* Click on the '+' to add a header
* Type some text that you can distinguish later ('header 1') for example
* Press 'Enter' key till next page
Current behavior: the header of the second page will also be 'header 1' -> CORRECT behavior.
* Click on the header on the second page
* Select 'Format Header...' in the drop down list
* Tab 'Header'
* Uncheck 'Same content on first page'
* Alter the header on the second page so you can distinguish it from the header on first page (for example: 'header 2')
* Save file as odt
* Save the file again as docx
* Reopen docx document
Current behavior: the header on the first page is replaced by the header of the second page. When you go back to 'Format Header...'->'Header' you'll see that 'Same content on first page' is checked again.
@Miklos: <offtopic>nice to met you at FOSDEM :-)</offtopic>.
Ontopic now: following https://wiki.documentfoundation.org/ReleaseNotes/4.0 I can see this is a feature you introduced (thanks for that). So I hope you're the right person to 'ping'.
Thanks for your time.
PS: opening odt file again -> good behavior. So I suppose there is something wrong in the export filter for docx.
This can be marked as NEW as it is confirmed.
Version 184.108.40.206.alpha0+ (Build ID: 027bb41aa16793e88e9fc1b3550c8c893363647)
Normal (can prevent high quality work for .docx)
High (bumped up from medium, new feature should function correctly, relatively common feature especially for professional work)
I can't reproduce anymore with LibreOffice Version 220.127.116.11.alpha0+ (Build ID: 67fbad1d1d593416136264aefb66d324e8e75bd).
This bug is fixed thanks to Luke Deller: https://gerrit.libreoffice.org/#/c/2065/ or https://gerrit.libreoffice.org/#/c/2062/
Therefore I don't mark it as WFM but as FIXED