If you don’t think it’s the page builder app causing this, it could be another plugin. Try deactivating all plugins to see if that makes a difference. Be sure caching is not confusing your investigation. If you get normal pages without plugins, restore your plugins, one at a time, until the problem returns. The last one activated is the cause.

BTW, this isn’t a “Developing” topic, I’m moving your topic to “Fixing WordPress”. The topic’s URL remains unchanged.