Consider the attached sample document created in Microsoft Office,
finally saved in Office 365.
When viewed in Office 365 there is a green blurry border around each
of the images on the slide.
In LibreOffice 126.96.36.199 as well as 188.8.131.52.alpha0+ those borders are
simply missing (though retained, i.e., when editing the document in
LibreOffice and then viewing in Office again, nothing seems lost).
Created attachment 152790 [details]
Sample slide (PPTX)
Created attachment 152791 [details]
How it should look (e.g., Office 365)
Created attachment 152792 [details]
How it actually looks (LibreOffice)
That is the "Glow" effect. It is a missing feature, same as other effects.
We should consider to make such reports duplicate to bug 101181.