InDesign Italic words issue

Okay, I'm going to assume that you want to keep the italics if the whole word is italic. So here's a revised script that should work with your test. And screen shots of my test results.

- Mark

/**
 * Removes italics fontStyle in an any word that is not completely italicized.
 * @7111211 m1b
 * discussion https://community.adobe.com/t5/indesign-discussions/indesign-italic-words-issue/m-p/13601388
 */
function main() {

    var findFontStyle = 'Italic',
        changeToFontStyle = 'Regular';

    app.findGrepPreferences = NothingEnum.NOTHING;
    app.changeGrepPreferences = NothingEnum.NOTHING;
    app.findGrepPreferences.findWhat = '[[:punct:]]?\\b[\\l\\u]+';
    app.findGrepPreferences.fontStyle = findFontStyle;

    app.findChangeGrepOptions.includeFootnotes = true;
    app.findChangeGrepOptions.includeHiddenLayers = true;
    app.findChangeGrepOptions.includeLockedLayersForFind = false;
    app.findChangeGrepOptions.includeLockedStoriesForFind = false;
    app.findChangeGrepOptions.includeMasterPages = true;

    var doc = app.activeDocument,
        found = doc.findGrep(),
        lettersOfWord = /[A-Za-z]+/,
        counter = 0;

    for (var i = 0; i < found.length; i++) {

        var word = found[i].words.item(0);

        if (!word.isValid)
            continue;

        var wordLettersMatch = word.contents.match(lettersOfWord);

        if (wordLettersMatch && wordLettersMatch[0].length > found[i].contents.length) {
            found[i].fontStyle = changeToFontStyle;
            counter++;
        }
    }

    alert('Changed ' + counter + ' partially italicized words.');

} // end main

app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Un-italicize Partial Words');