I noticed this the other day also so thought I would report it. I just updated the icon for a Resource and the new icon image does not load completely. I tried a hard reload but that didn't work either.
In this case, we think it might be some sort of CloudFlare quirk though we're not positive if that's where it's happening. We've occasionally seen some similar type of issues when we make JS changes. Unfortunately, not much we can do about it as the correct file would be on disk and that's what XF would've setup and the web browser would be serving. Perhaps something incomplete got stuck in a cache somewhere.