## 🐛 Bug Report

Running with java binding and Firefox, the framework occasionally throws NullPointerException on the isDisplayed call.

**Please see https://github.com/mozilla/geckodriver/issues/1825 for more information.** As stated from geckodriver team, the issue is apparently related to the custom JS that is executed with this method. The ticket also contains trace logs. 

## To Reproduce

Hard to provide steps, as it happens "randomly".

## Expected behavior

Should not throw exception..

## Environment

OS: Windows 10
Browser: Firefox
Browser version: 84.0.1
Browser Driver version: geckodriver 0.28.0 (c00d2b6acd3f 2020-11-03 16:29 +0200)
Language Bindings version: java 3.141.59

.getValue();
    try {
      return (Boolean) value;
    } catch (ClassCastException ex) {
      throw new WebDriverException("Returned value cannot be converted to Boolean: " + value, ex);
    }
  }
  @Override
  public String getText() {
    Response response = execute(DriverCommand.GET_ELEMENT_TEXT(id));
    return (String) response.getValue();
  }
  @Override
  public String getCssValue(String propertyName) {
    Response response = execute(DriverCommand.GET_ELEMENT_VALUE_OF_CSS_PROPERTY(id, propertyName));
    return (String) response.getValue();
  }
  @Override
  public List<WebElement> findElements(By locator) {
    return parent.findElements(parent, this, locator);
  }
  @Override
  public WebElement findElement(By locator) {
    return parent.findElement(parent, this, locator);
  }
  /**
   * @deprecated Rely on using {@link By.Remotable} instead
   */
  @Deprecated
  protected WebElement findElement(String using, String value) {