Sounds like some people are getting missing radical issues for the image-based radicals. You updated those, I presume? Is there some kind of server-side force-refresh you can do?
The file path is exactly the same, so the image should load (either the cached old version or the new one). It shouldn’t show up missing.
Inspecting a page with radical images loaded it looks like the image path is missing the file extension. If I had to make a guess this is cause of the loading issue for some people. I’ll look into getting this fixed.