Description:
LibreOffice crashes using mailmerge and exporting the file as PDF individual documents

Steps to Reproduce:
1. Create a new ODT file
2. Insert -> field -> more fields...
3. Select the "Database" tab
4. Click on "browse" and select the "sorgente-test.ods"
5. double click on "sorgente-test.ods"
6. double click on "foglio 1"
7. double click on "field1" "field2" field3"
8. click on close
9. file -> print -> "yes"
10. Select the radiobutton "all records"
11. as "output" select "file" and "save as individual documents"
12. check "generate file name from database"
13. as field select "field1"
14. as path select your destination folder
15. as file format select "PDF"
16. click "ok"

Actual Results:  
LibreOffice crashes and in the destination folder is generated only the first pdf.

Expected Results:
All the PDF are generated and LibreOffice is still running


Reproducible: Always


User Profile Reset: Yes



Additional Info:
Nome modello: Mac mini
Identificatore modello: Macmini6,1
Nome processore: Intel Core i5
Velocità processore: 2,5 GHz
Numero di processori: 1
Numero totale di Core: 2
Cache L2 (per Core): 256 KB
Cache L3: 3 MB
Memoria: 4 GB
Versione Boot ROM: MM61.010B.B00
Versione SMC (sistema): 2.7f0

repro on:
Versione: 6.0.2.1
Build ID: f7f06a8f319e4b62f9bc5095aa112a65d2f3ac89
Thread CPU: 4; SO: Mac OS X 10.12.6; Resa interfaccia: predefinito; 
Versione locale: it-IT (it_IT.UTF-8); Calc: group

repro on:
Versione: 6.0.1.1
Build ID: 60bfb1526849283ce2491346ed2aa51c465abfe6
Thread CPU: 4; SO: Mac OS X 10.13.3; Resa interfaccia: predefinito; 
Versione locale: it-IT (it_IT.UTF-8); Calc: group


works fine on:
Version: 5.2.5.1
Build ID: 0312e1a284a7d50ca85a365c316c7abbf20a4d22
CPU Threads: 4; OS Version: Mac OS X 10.13.3; UI Render: default; 
Locale: it-IT (en_IT.UTF-8); Calc: group 


User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:59.0) Gecko/20100101 Firefox/59.0