Clearing character highlighting leaves behind a white highlight color which persists even when setting character highlight to transparent. This effect is carried through copying and pasting effected text. The only fix I have found so far is to completely clear all applied formatting (ctrl + M), however this solution isn’t optimal as it expectedly removes other specific formatting I’ve applied, and likewise this persistent highlight seems to have become a component of some of my heading styles. My document uses a textured background, making this effect very apparent. I’ve also tried changing theme settings, but this hasn’t been successful.
Welcome to direct formatting hell. You would be better advised to use styles to format your document, a little more work initially and a lot less overall. See the Writer Guide, download from English documentation | LibreOffice Documentation - LibreOffice User Guides also at the bottom of that page, if you click on More it will take you to a second page with a link to Designing with LibreOffice which explains why using styles is a lot easier than direct formatting.
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If clicking clear character formatting doesn’t remove the white background (document came from Word?) then the white background must be defined in the paragraph formatting. If it is cleared by Ctrl+M then it is a direct formatted paragraph. Right click in the paragraph and select Paragraph. In the dialogue that opens, select Font effects tab and the background to Automatic.
@cm713,
If do you edit your question and uploads there a reduced sample file showing the issue, we can test and give a better answer.