Description:
I have been using Libre Office for several years to create a newsletter for a small non-profit organisation of less than 200 members.
Recently I have found that the mailmerge print to file function to create a single file document with Member Names in the page header alters the document format in the output document and only merges the Member Name on the first page of the document.  Sometimes Libre Office crashes during the merge process.

Steps to Reproduce:
1.Create a base .odt document (2-4 pages) with a page header.
2.Link the document to an Exchange Database - a two column .ods spreadsheet containing first name and last name of each member.
3.View Datasources and insert the first name and last name fields into the page header.
4. Save the document.
5. Print the document, which is recognised as a merged document, and choose to print a form letter.
6. Select Records = All, Output = File, Save as single document.
7. Save the output file with a new name.  Sometimes crashes at this point.
8. Open the output file.

Actual Results:
The output file includes multiple copies of the base file as expected.  The page header of each copy includes the member first name and last name only on the first page and field markers <FIRST> <LAST> on the remaining pages.
Page format is also different from the base document with text overflowing to the following page.

Expected Results:
The member first name and last name should appear on each page of each copy in the output file.
The page format should be identical to the base document.


Reproducible: Always


User Profile Reset: No



Additional Info:
crashreport.libreoffice.org/stats/crash_details/7c27a937-924b-4e10-8f0a-f53cbbb075f1
submitted.
Version: 6.4.6.2 (x64)
Build ID: 0ce51a4fd21bff07a5c061082cc82c5ed232f115
CPU threads: 4; OS: Windows 10.0 Build 18363; UI render: GL; VCL: win; 
Locale: en-AU (en_AU); UI-Language: en-GB
Calc: threaded