SharePoint 2007 Search Quirk–Hit Highlighting on Integers

While working on a SharePoint 2007 custom search project we found an interesting little quirk in the search engine.

We were using the XML iFilter rather than the regular html iFilter due to a requirement to tightly constrain some date metadata as type datetime (with the OOTB filter SharePoint was returning these as text and not allowing proper date range filtering).

While searching for numbers contained within text, if the number was on its own line of text and not preceded by anything else, the result would return correctly but hit-highlighting was not applied.

However, if we put any text at all in front of the numbers, the hit-highlighting applies perfectly.

Therefore the workaround was simply to alter the text that was being displayed to include at least one letter or word before the integers in the line.