Created attachment 185462 [details]
document with color theme
Open attached document. It a theme in styles.xml.
The characters in the file are direct formatted to use a theme color. You can verify in the file markup, that this is indeed contained in the file markup.
Save the file to docx. Open the file in Word and change the theme of Word (that is in tab 'Design'). The colors of the characters do not change, which means, that they do not have theme colors.
Inspect the markup of the docx file. You will find that the needed attributes "w:themeColor" and "w:themeTint" or "w:themeShade" of the <w:color> element are missing.
Version: 184.108.40.206.alpha0+ (X86_64) / LibreOffice Community
Build ID: e4e5fb4b2935e395c7e4b3a794d544a6f44709ce
CPU threads: 15; OS: Windows 10.0 Build 19045; UI render: default; VCL: win
Locale: de-DE (hu_HU); UI: en-US