Hey Szmigieldesign,
There still needs to be some research on this, it seems to be an issue with ZipArchive and the inbound json file. The same issue still happens for Ziparchive on the pro version, however when shell_exec is used the UTF8 file names are preserved. Unfortunately shell_exec is only available in the pro version. We are still looking for a resolution for ZipArchive for both versions...
Thanks~