Hi Rui,
I understand; I’m a developer, too. I’m sure you get lots of requests to fix issues that aren’t your responsibility, but since this happened to me the first time on a clean install of your theme and required/recommended plugins, and later again after updating the Swift framework, I don’t think that it’s prudent to assume that the problem lies with a third-party plugin.
Before this issue re-occurred, I installed the Custom Permalinks and WordPress Importer plugins. Looking through their code, I don’t see anything that jumps out at me that would conflict with the page builder. Here is my full list of active plugins:
Advanced Custom Fields
Akismet
Atelier Demo Content
Breadcrumb NavXT
Contact Form 7
Custom Permalinks
Go – Responsive Pricing & Compare Tables
oAuth Twitter Feed for Developers
Swift Framework
WooCommerce
WooCommerce Quickview
WordPress Importer
WordPress SEO
YITH WooCommerce Wishlist
At the moment, everything’s working just fine since my last fix this morning.