In most newspaper archives especially Google Newspapers, DON'T depend on the search engines to find information. Most use OCR to "read" the newspaper. OCR is only about 70% accurate if you are lucky. Blurred letters, letters that are misshapen, or that are two close together cause problems with OCR.
Additionally in Google newspapers, when all of the pages are not in the same orientation, OCR misses the whole page. I have found these problems in a page by page searches, and the information I needed was on one of these miss oriented pages.
One other thing about Google Newspapers. While some times dates are missing because there was no paper printed on that day, many times multiple days papers will appear as one date. Again the only way to pick this up is on a page by page search. Some time but not always you can get clues when you open the newspaper and you see more pages than the average newspaper for that time frame, but not always.