Spotlight does not find content in Numbers

Spotlight doesn't work with Numbers (version 5.3 (5989)), but everything else. In System Preferences>Spotlight, I do have Spreadsheets selected. I have rebuilt the index in the manner of adding the hard drive to System Preferences>Spotlight>Privacy and then removing it from Privacy, to no avail. The same word can added to a Pages document and a Numbers spreadsheet and Spotlight will find the document but not the spreadsheet. MacOS 10.13.6.