Disclosure: I work for DeepMind on the AlphaZero project, but everything I say here is personal opinion and does not reflect the views of DeepMind / Alphabet.
Gerd noticed it and we have sent in a complaint to the wikispaces people. Somehow they have cross linked our pages with pages from something else. Something similar happened in March which forced Gerd to have to change 100+ pages back.
I have not heard back from the wikispaces people yet, which is very disappointing.
Seems Wikispaces has some hash collissions We may revert page for page, but prefer they may find the bug to revert all mixed up pages in one run. So far, for a wrong page, click on revsions (button with the clock top right), and choose latest revision, i.e. ...
A few pages were reverted manually, but most pages I found broken yesterday were already restored. I am actually too lazy to check all ~3900 pages, please send me pm or message in cpw if you still find mixed up pages. Hope this does not happen again.