The same problem had been there on our live website too. We just moved our website from a Media Temple server to Kinsta server. While migrating to new server, we took time to do it properly this time by creating a child theme and move all theme modifications we did (very little) to child theme. And then we installed the new upgraded theme too because I was stuck with old swift theme due to the changes I made to core theme and not been able to document it. Finally up with new theme and saw this text builder disappeared from old pages and new pages. I took three days trying to figure out the problem but to no good. Finally, I gave it up and renewed the support on themeforest to get your guys hands in.
I am lucky that I paid attention to the recent posts and came across reddion post. Thanks mate.
@Rui you’re a life saver. Thanks for the awesome support. I cleared the cache, restarted PHP 7, and replaced the shortcodes.php file. And the page in edit mode is back in action as it should be. Thanks a lot.
Best regards
Dani Gorgon