Update 2: I switched the theme to Twenty Twenty to text if it was related to GeneratePress it is not. The Twenty Twenty theme showed the same results, broken columns. I have also tried switching the PHP version but that made no difference.
Comparing your working site and the test version I can see that some of the required styles are missing on the test version.
But when I test the same on my own test site those style definitions are included. That's after updating to Blocks 1.6.12.
Could we get access to your test site, where it is not working, to see if we can identify the problem?
Let me mark your next reply as private so that we can get log-in credentials from you—you may want to create a temporary admin user for us to use that you can later delete. And be sure to have a current backup of your site.