I am having exact same issue. What is the solution?
I have an issue with SP Page Builder - the builder is not expanding. I am running the latest version of SP Page Builder and Joomla! 3.10.9 - the issue is on the page "Contact Trench Shoring Company". https://tinyurl.com/2yuq34zc
The Page Builder is ok on the "About Us" Page
Template is Shaper_corporex
Hosting is Ionos
PHP Version 7.4.29
Database mysql, 5.7.38-log
Editor: Default is TinyMCE (we do have JCE installed)
I believe that cloudflare is enabled, and this is controlled by the IT Manager