Problem is caused by a beta feature in Windows 10 build 1803. To disable the offended beta feature:

• Start-Control Panel
• Select Region
• Click 'Change system locale' on the Administrative tab
• Uncheck 'Beta: Use Unicode UTF-8 for worldwide language support'
• Click Ok (will have to reboot)

Hopefully, this feature will be fixed before it is actually released. We can only hope :).