Concordance results differ from PDF search for the same word

Hi, I’m looking at a PDF I have imported and OCR’d. When I search for a word, I get a different number of occurrences from the concordance number – even when the concordance line is greyed out and the word only appears in one document. (Search: 68 occurrences, Concordance: frequency 133.) Is there something I am missing or misreading?

A copy of the document would be great, could you send it to cgrunenberg - at - and the used search term too? Thanks!