Subsite still Old UI After Visual Upgrade

Hi,

I'm using SharePoint Foundation 2010. I have performed Visual Upgrade but some of the subsites are still using the old look. May I know what can I do? Appreciate any guidelines. Thank you.

This is what I have tried:

-at site collection, Site settings->Site Collection Administration->Visual Upgrade->Update All Sites ==>still the old look

-powershell script ==>still the old look

$site = Get-SPWeb http://server/site/subsite
$site.UIVersion = 4
$site.UIVersionConfigurationEnabled = 0
$site.Update()