Writer changes font to default when printing landscape

When I print a Writer document in landscape orientation, whatever the assigned fonts, they are overridden and replaced by the default font (Liberation Serif size 12).
Writer is OK with portrait orientation.
How can I get Writer to behave properly?

Libreoffice Version: 6.4.7.2

Linux ryzen-DB 5.4.0-91-generic #102-Ubuntu SMP x86_64 GNU/Linux

What file format are you saving in?

Well, I think that can only be guessed without looking at the document. Upload a reduced and anonymized sample document here.


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Thank you.

Various; but most commonly Nimbus Roman 12.
Whichever I use is printed correctly so long as the page orientation is Portrait.
Once I change the page orientation to Landscape, the font type, size, bolding, italicisation are ignored and all text is printed Liberation Serif 12.
I’ve tried ringing changes on the Printer Language Type in Printer Properties setting; that makes no difference.