Assets in CC Library appear with a white background (because of that white graphics are not visible)

Some assests in my CC Library appear with a white background, and because of that white graphics are not visible at all.

I've tried several workarounds found on the Community forums like a) opening the asset with Edit, making an adjustment (group and ungroup) and hitting Save, and b) placing a PDF and making sure options are for having a transparent background, and after that reimporting graphics to CC Library, but nothing has helped.

I use InDesign 19.5 most of the time, but it's the same working in Illustrator 28.7.1 as well. I work with M1 MacBook Air and macOS Ventura 13.6.9.

What takes? Why do some of my assets have white backgrounds and some don't?