User blog comment:DaNASCAT/Technical Update: April 22, 2015/@comment-11387016-20150423183238

Can't say if it's related to the update or not, but sometimes, we have it that pages don't show up after an edit, they just end up totally empty (noticed this twice today). A double undo fixes this issue, but I think it would be better if this would get solved at the core of the problem.