An boolean property with the defaultValue TRUE, set to False and export via flow site:export endsup as in the xml export file.
If I import this and run flow repair:node afterwared it’s value is set to the defaultValue TRUE.
As an workaround i changed the defaultValue to False, that way it works.
Not so sure which package that bugs belongs to so i report it here.
Update: Seems the defaultValue is also applied for empty text properties after an import.