Hello,
In 10 years with Adsense, I never had a single warning, or notification, or problems (beside earnings decrease).
Two days ago, I get a warning notification, saying that one page of one of my site, was presenting a problem with its content. The notification, was clear, this is not a "big deal", it said that, ad inventory might be restricted on this particular page, depending of Advertisers' settings. (this is the new rules, appeared last year).
At my account, I could see the page and detail about it.
Today, the page is no longer showing in the restriction page.
Does it mean that Adsense cancelled the restriction by itself? I didn't ask for a review.