No unicode characters in pdf form fields

Hello
I am creating a fillable pdf form but i have problem with the greek characters as they are missing when i fill the fields.PDF forms created with LibreOffice show only latin characters in form fields.
Maybe it is a bug or there is something i can do to solve this problem?

Thank you in advance

Please give instructions on how to reproduce the problem. I created a form based on this example and set the default text of the text box to αβγδε. It displayed correctly in PDF.

I confirm the bug wrote by falcongr. Don’t appear characters non-unicode in PDF forms…
I use LibreOffice 6.0.1 Portable.
Please fix this bug.

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