Resolved (15 September 2026): This issue has been fixed — CSV exports no longer show garbled text when opened directly in Excel. The steps below are kept for reference.
Here are the steps to open a CSV file in Excel without character encoding issues.
Launch Excel.
Select [Blank workbook] to create a new workbook.
In the new workbook, click the [Data] tab on the ribbon menu.
Click [From Text/CSV] and select the CSV file you wish to open (the file exported from Flow).
Click [Import] or [Transform Data].