After Germany's defeat in 1918, generals, who had influence, published papers that suggested that von Moltke had not fulfilled 'the Schlieffen plan'. This started in 1919 with the writings of Hans Delbruck and continued with Wolfgang Foerster, Hermann von Kuhl and, of course, Ludendorff. Their claim was that von Moltke failed to strengthen the right wing of the German army for its sweep around Paris.
The figures quoted by Ludendorff in 1930 included hypothetical figures for the right wing which could never have been fulfilled, as the land army was not strong enough. We do have the writings of Wilhelm Dieckmann, a wartime officer and economic historian. Starting in 1920 and working with a copy of the 1905 staff ride, he pointed out that von Schlieffen never meant the German army to sweep around Paris. Unfortunately Dieckmann was arrested and executed after the July 1944 plot so his work only surfaced after the reunification of the two Germanies.
Why do we bother with this hiccup in world history? Because the failed German generals, remembering the imperial victories of the 19th century, claimed that a mythical plan had not been fulfilled. Germany went to war in 1914 with von Moltke's plan, which failed. Just as every major German offensive on the western front failed including the 1918 offensive. Unfortunately, these generals went on to become supporters of Herr Hitler and initiated a Second World War.