Currently, I’m using mPDF to create PDF/A files in PHP.
SVGs have a transparent background by default. But this breaks compatibility to PDF/A. When validation such a PDF file using veraPDF, I get an error, saying “A Group object with an S key with a value of Transparency shall not be included in a form XObject. A Group object with an S key with a value of Transparency shall not be included in a page dictionary”

I’ve tried to a add a rect to the SVG (like it is stated here) but have not had luck.
Is there a solution to remove this transparency but still being able to use SVGs?