JabRef 5.1--2020-08-30--e023aa0
Ubuntu 18.04.3 LTS
Java 14.0.2
Libreoffice 6.0.7.3

• Mandatory: I have tested the latest development version from http://builds.jabref.org/master/ and the problem persists

Instead of showing a Number in brackets as citation when using the "default [Number] style file" a minus sign with space "- " is printed when citing in LibreOffice. The "default [Author] style file" works as expected though.

Steps to reproduce the behavior:

1. Connect to LibreOffice Document
2. Select citation style "Default [Number] style file"
3. Cite a reference by clicking on "cite" or "cite in text"
4. The citation in Libreoffice will only contain a "- " and no Number or brackets

The bug can be reproduced with any reference I choose. I also tried to define my own copy of the default number style file from this file src/main/resources/resource/openoffice/default_numerical.jstyle but I get the same output (minus sign with space instead of Number in brackets).