Blender 3.0 Asset Browser Not Rendering Thumbnail 14/15 Items

I’m find that very few assets will render a thumbnail when I press the generate thumbnail button. 1 out of 15 items I tried would render thumbnail. The rest just remain as generic doc icons.

I downloaded a few assets from BlenderKit, arranged them in a new project, saved project as “assets.blend” and then proceed to mark as asset, each model. They appear as shown below with no useful thumbnails. Only a two had thumbnails. I was able to get two more to force render a thumbnail when I selected them and hit the render thumbnail. Bug?

You probably already found This other forum post but if not I hope it helps someone else who comes across this, as it was the first thing that came up for me when searching. Anyway, looks like you just need to give it more time to generate the thumbnails. Your case might be different, but I think for most coming to this thread, this will help.

It’s been several months and it still hasn’t rendered the rest of the thumbnails. And my machine isn’t low end (i7-9770K with RTX3090).
I think there’s something about a lot of Blenderkit assets that prevent putting them in the library and properly rendering thumbnails.