Garbled characters when exporting contacts to .vcf

I’m trying to export my contacts via “Export contacts to .vcf files”, but Unicode (?) characters end up garbled in the export file (they are perfectly fine in eMClient).

ö becomes ö
姚艳霞 becomes 姚艳霞

I’d appreciate a way to fix this. Thanks in advance!

(Apologies if this has been asked before, I could not find that thread then, sorry.)