Wait, the pages has been restored, right?
We do have a backup but basically the page does not disappear, it is just not properly displayed sometimes if you click Undo button after saving the page. In this case, do not click Undo again, first go to another page and then return to it.
If this does not address your concern, send us an email and we will setup a call to discuss further.
Dmitry Buterin, Chief Apricot