In WWE's kayfabe magazine, there are some major errors that have been published.
In an article looking at an Evolution timeline, Batista's match with the Undertaker is described taking place in 2007 at Wrestlemania 22, when it was obviously Wrestlemania 23 that took place that year.
Another error involving The Undertaker takes place in the Summerslam quiz. Question 2 asks which wrestler didn't face Undertaker in a Summerslam match with the choices of Edge, Steve Austin, Kurt Angle and Chris Jericho. Both Jericho and Angle didn't face the Undertaker at Summerslam.