Hi, Ivan!
Please attach a small demo project with a data model that is used inside the report and a report zip archive (you can get it by pressing the “Export” button at the “Reports” screen).
There is a bug in the Reporting module. The table is not filled if the last cell contains an alias with the “.” symbol (${producto.ref} in you case). As a workaround, you can move this column somewhere in the middle of the table and everything will work.
We will fix the issue in one of next releases. Thank you for reporting it.