So I’ve been looking at that support article that’s also gone missing … ironically!!
Weirdly, there are still links to that page in several areas. If you go to the support pages and search for guild vault missing items, it provides the link to the empty page.
It is also mentioned on the TWW Common Issues article:
https://eu.battle.net/support/en/help/article/000358474
Although the link again only goes to the empty page.
Either they’re trying to clear reference to it and forgot to remove the links to it, or the support page (on both EU and US) got accidentally wiped. Perhaps they’ll find that in the same place as our guild vault contents …
Edit … I’ve raised an issue about it: