Created attachment 93233 [details]
the resulting odt with wrongly duplicated headers

The information first page header / odd page header / even page header gets scrambled if an object (e.g. text frame) is inserted into the header. After a save / load cycle, the inserted object appears duplicated into the wrong headers (e.g. odd pages, even so it was only inserted for even pages)

Steps to reproduce:

Create a new document

Format / Page / Header
  Select Header on
  Deselect "Same content left/right"
  Deselect "Same content on first page"

Insert page break

On page 2, insert a text frame into the header into the header. Enter text "Even page" into the text frame.

Insert page break

On page 3, insert a text frame into the header into the header. Enter text "Odd page" into the text frame.

So far, behaviour is correct: no header on page one, and text-frames with "Even page" on all even pages, text-frames with "Odd page" on all odd pages > 1.

BUG: saving and reloading the document (as standard ODT format) corrupts this header setup:

Now save the document as "Test.odt"
Quit LibreOffice
And open the document "Test.odt" again.

The header is now corrupted/duplicated to the wrong pages:
On page 1, "Odd page" appears (expected behavior: no text box on page 1)
On all even pages, we have now two text boxes (possibly on top of each other): one with "Odd page" and one with "even page". (expected: as before "odd page" should only appear on odd pages, similar with "even pages).

This bug is quite severe, since it alters a document without user interaction. It's not possible for a user to fix this permanently. Each time, extra-copies of unwanted text frames are deleted, this only holds until next save / open cycle: Again unwanted frames manifest. The document corrupts itself on each save.