Shape marked as decorative still failing accessibility checker in Writer

I have a document, that was created in Word, opened in libre office.
In the document ( Newsletter) there are shapes ( Rectangles) that were inserted for deliniation of Articles etc… and every one of them failed the Accessibility checker, even though they have been marked as decorative ?

Any ideas please ?

Thank you in advance for your kind assistance. !

The shapes would be exported to pdf as decorative, if PDF/UA or Tagged is checked, since 7.5.2, see tdf#143311. You might care to read about the decorative flag and ODF 1.3 in that same bug report.

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Paragraph borders or underlinings are handled without problem by accessibility checker.