Cloudflare data still in Bing caches
From the parent thread:  The caches other than Google were quick to clear and we've not been able to find active data on them any longer.
  ...
  I agree it's troubling that Google is taking so long.

That's really the core issue here - the Cloudflare CEO singled out Google as almost being complicit in making their problem worse whilst that exact issue is prevalent amongst other indexes too.The leaked information is hard to pinpoint in general, let alone amongst indexes containing billions of pages.I can understand the frustration - this is a major issue for Cloudflare and it's in everyone's best interests for the cached data to disappear - but it's not easy, and they shouldn't say as such (or incorrectly claim that "The leaked memory has been purged with the help of the search engines" on their blog post).This is a burden that Cloudflare has placed on the internet community.
Each of those indexes - Google, Microsoft Bing, Yahoo, DDG, Baidu, Yandex, ... - have to fix a complicated problem not of their creation.
They don't really have a choice either given that the leak contains personally identifiable information - it really is a special sort of hell they've unleashed.Having previously been part of Common Crawl and knowing many people at Internet Archive, I'm personally slighted. I'm sure it's hellish for the commercial indexes above to properly handle this let alone for non-profits with limited resources.Flushing everything from a domain isn't a solution - that'd mean deleting history. For Common Crawl or Internet Archive, that's directly against their fundamental purpose.