I confirm the answer from Todd. Now that VTK expects UTF8 encoded strings, you must force the active codepage to UTF8 by adding the following section in your app.manifest file:
<application xmlns="urn:schemas-microsoft-com:asm.v3">
<windowsSettings>
<activeCodePage xmlns="http://schemas.microsoft.com/SMI/2019/WindowsSettings">UTF-8</activeCodePage>
</windowsSettings>
</application>
This has been fixed recently and won’t be required anymore in the next Activiz version that will be released before the end of the month.