Selenium Internet Explorer 11 driver doesn't starting in private mode

[AndrewBystrov]

Meta -

OS: Windows 7

Selenium Version: 3.8.1

Browser: Internet Explorer

Browser Version: 11.0.9600.18349 (64-bit)

Expected Behavior -

Starting IE on private mode ( via use create force api and command line switches)

Actual Behavior -

IE started not in private mode

Steps to reproduce -

InternetExplorerOptions ieOptions = new InternetExplorerOptions();
ieOptions.setCapability("ie.enableFullPageScreenshot", false);
ieOptions.setCapability(InternetExplorerDriver.ENABLE_PERSISTENT_HOVERING, false);
ieOptions.setCapability(InternetExplorerDriver.LOG_FILE, "ieDriver.log"));
ieOptions.setCapability(InternetExplorerDriver.LOG_LEVEL, "DEBUG");
ieOptions.setCapability(InternetExplorerDriver.FORCE_CREATE_PROCESS, true);
ieOptions.setCapability(InternetExplorerDriver.IE_SWITCHES, Collections.singletonList("-private"));
InternetExplorerDriver driver = new InternetExplorerDriver(ieOptions);
driver.manage().window().maximize();

WebElement input = driver.findElement(By.id("input"));
driver.quit();

Capability InternetExplorerDriver.IE_SWITCHES requered value as list, but on the ieDriver.log I see the warn
CommandHandlers\NewSessionCommandHandler.cpp(105) Invalid capability setting: ie.browserCommandLineSwitches is type array instead of string. Default value will be used: "" and the IE doesn't start on the private mode.

Any ideas about it?

Thanks.

ieDriver.log