The editorial approval process for adcenter has always been pretty obtuse, but today they seem to have the adbot crawling and denying ads based on the landing page content. It seems that the adbot has a long list of prohibited phrases and if it find this text string anywhere on the page, *poof*.
I'm seeing a lot of collateral damage. If a landing page product description happens to have an offending string, even as a substring of a larger string, then the keyword is denied. The most ludicrous, two characters, yes, a sequence of two characters, can trigger an editorial denial, for example, the string "X1" (made this one up), as in aaa-bbb-X3-x1