PDF outline doesn't respect style

I have a problem with the formatting of PDFs that are exported from LibreOffice Writer.

The resultant PDF outline includes some random pieces of text as well as headings.
Heading 3 (this is a style) seems to be the culprit.
What appears to be happening is that the first line of every paragraph after a Heading 3 is shown in the outline which defeats the purpose of the outline.

Does anyone know how to fix this?

Are you 100% sure that the "faulty paragraphs are not Heading 3 styled with an extra direct formatting to change font properties? Please check the paragraph drop-down menu and apply Ctrl+M (clear direct formatting) on the paragraphs.