1897: ‘… is almost sure to misunderstand and misunderestimate the significance of the question at hand’ (anonymous, ‘American Diplomacy on the Bosphorus’, The Outlook).
1975: ‘Now in the very earliest years of the eighteenth century it is understandable that, owing to the inevitable, due to our never-to-be-misunderestimated Frederick the Gross …’ (Thomas Merton, My Argument with the Gestapo).
1980: ‘And I think after Three Mile Island, not only does the NRC itself understand that it sadly misunderestimated the number of ways in …’ (Accident at the Three Mile Island Nuclear Powerplant, House Committee on Interior and Insular Affairs, Subcommittee on Energy and the Environment. US GPO, 1980).
1992: ‘John helped Christians to see how the Synoptic writers, and not only the disciples within their accounts, had seriously misunderestimated the life and …’ (Adelbert Denaux, John and the Synoptics).
1997: ‘If you misunderestimate the power of the intense bureaucracy in these agencies and departments and federal institutions, you go, they stay’ (John Conyers, Jr.).
Have journalists ever heard of Google searches? Has anyone?