I’m having the same issue. I have raised a jira ticket.
It looks to me like there is an issue with the postgreSQL database as the dashboard.php page is not populating with data from the database as shown in the walkthrough screenshots.
Also if there is a database issue, the search field may not actually be passing user input to the database as query, which would be a cause for sqlmap to not find any injection vulnerabilities as it is effectively just a ‘dumb’ search box right now.
On the bright side, if you are not familiar with SQL databases and how web pages interact with them, this could be a nice opportunity to get a better understanding of what could be going wrong here.
I ran into the same issue today and solved it by deleting my session cookie redoing the login on the website and redoing the sqlmap with the new session id. Sqlmap than produced the expected output.
Before I deleted my session cookie I had the same issue that no entries showed up in the dashboard.