I've had a quick google and it suggested it maybe these reg keys which are changed when ticking the box in the UI.
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\CodePage]
"ACP"="65001"
"OEMCP"="65001"
"MACCP"="65001"
You could maybe set those ( sounds like a restart might be needed too)