When exporting reports or other data to create Excel and/or CSV files extended characters might not display correctly in the created file.
Examples for extended characters: é ñ ĝ ä ǰ ḁ ṓ

This article explains how to make sure the extended characters are displaying correctly
https://support.youcanbook.me/article/502-how-can-i-get-excel-to-properly-display-special-characters-in-the-data-export