In Dutch records, often only the right page is numbered. So if you see a reference for your ancestor at page 15 and can’t find her, turn the page and check the left side of page 16.
Often, this reverse page is designated like fol. 15v, with a v for “verso” [Latin for reverse] and “fol.” [folio] instead of p. [page]. But sometimes the numbers look like regular page numbers and don’t give a clue that the record could be on the reverse page. One place where I’ve noticed this happening is in Friesland civil registration records.