Dutch date format gets lost when saving

[GerritEzn]

I am using LO writer under a Linux operating system with standard US-English settings.

When ever I write a document in Dutch
the standard date field has a US-English format.
I select Dutch as language for the document en
update the format for the date field to be Dutch.
Everything OK.

However when I save the document and reopen it,
the date field format is back to US-English.

Is there something to do about it?
It seems that the windows version does not have this problem.

Gerrit

System: Host: Olga Kernel: 4.14.13-pclos1 x86_64 bits: 64
Desktop: MATE 1.18.0 Distro: PCLinuxOS

LO:
Version: 5.4.4.2
Build ID: 2524958677847fb3bb44820e40380acbe820f960
CPU threads: 2; OS: Linux 4.14; UI render: default; VCL: gtk2;
Locale: nl-NL (en_US.UTF-8); Calc: group

[GerritEzn]

On the PCLinuxOS forum this solution was suggested:

When I

• set Options; Default language for documents to Dutch
• set Options: the locale setting to Dutch,
• and set the language for all text to Dutch
  and then enter date fields the Dutch format sticks.

I note now that not-withstanding these options new documents have English (UK) as
language.

Gerrit