You can download scraped items data from Scrapy Cloud in various formats like JSON, JSON Lines, CSV and XML.
Despite CSV format is pretty old and limited, it one of the most popular formats due its simplicity.
However CSV data exporter is implemented in Scrapy Cloud in its basic form and some advanced cases might not be handled properly.
One of the known issues is related with nested fields in items.
For example, if an item field's value is an array of strings having commas inside, there might be some issues when trying to read exported CSV because field values are also separated with commas.
We have plans to improve current CSV exporter implementation and the issues will be addressed in the future for sure.
Nonetheless if you encounter with such cases before it's fixed, we suggest to export data in some other format like JSON and convert it to CSV as needed via some script.