I have had issues with the latest update of SP Page Builder on multiple occasions and different websites. I have some offline.
I installed the quickstart of the Investa template, and everything worked fine until I updated to the latest version of SP Page Builder, and now I get the error: "Sorry, there was a problem we could not recover from. The server returned a "500 - Whoops, looks like something went wrong."
This has happened on other websites as well, and once it occurs, I have no way to recover it. It is worth mentioning that I can still access the backend.