This file was giving the same problem as in T216178: [BUG] SVGTranslate does not render previews and shows error popup. @Glrx went ahead and fixed the file but the svgtranslate tool still shows the cached version ~ one hour later (as of writing this ticket).
There was a problem with File:999-percentages.svg when used on toolforge. I suspect toolforge cached a local copy of the file. I uploaded a new version of the file to Commons and purged the Commons File: page. I suspect the purge invalidates conventional WMF servers but not toolforge's cache. Toolforge probably thinks the file is still fresh, so it does not contact Commons to see if the file is still current.
Yep, it's the tool caching the image. It caches for 5 hours and then starts deleting cached files (i.e. they can last for longer than 5 hours). It's definitely something we need to improve!
I think this task might be a duplicate of T213126: Re-check Commons file when using cached version.