This is the function that runs fine when a signed-in user changes the cell value, but not when someone not signed-in:

It does simple things with the sheet itself and in unprotected ranges.
I have seen online that it should fire even if the file is open in a tab which is in incongnito mode, but it doesn’t even show in the logs that the function has run.

function onEdit(e) {
  const sheet = e.range.getSheet();
  const sheetsToWatch = ['Content Workbook'];

  if (sheetsToWatch.includes(sheet.getName())) {
    const headers = sheet.getRange(1, 1, 1, sheet.getMaxColumns()).getValues()[0];
    const colToWatch = 'Client Feedback';
    const colToWatchIndex = headers.indexOf(colToWatch) + 1;
    const row = e.range.getRow();

    const colToSet = 'Feedback Processed';
    const colToSetIndex = headers.indexOf(colToSet) + 1;

    if (e.range.getColumn() === colToWatchIndex && row > 1) {
      const row = e.range.getRow();
      const timestamp = Utilities.formatDate(new Date(), Session.getScriptTimeZone(), "MM/dd/yyyy HH:mm:ss");
      sheet.getRange(row, colToSetIndex).setValue("No");
      sheet.getRange(row, colToSetIndex + 1).setValue(timestamp);
    }
  }
}