When using document generator the download of the document fails with "Error getting process status"

When using the document generator to export a template, occasionally the download fails after the process is finished with success. This is observed mainly for larger exports.

How to Reproduce 

1. Have a template and a large amount of data to export;
2. Export that template.

Actual Result

The export finishes with success, however, when the download button is clicked, the download fails with: "Error getting process status".

Expected Result

After clicking the download button the document is downloaded.