I downloaded and installed the ‘free’ version, created a new page, added a few widgets, and saved it. The page was saved without error. As the error is originating with Elementor, it is appropriate to notify the author of the plugin that’s failing. They will need to make the determination the problem is with Redux. If they discover one, they will need to be the ones to report it to us with the necessary data to look into it. It’s not a task I am able to do as I am not the author and I cannot recreate the issue. If it’s the Pro version you are using, that, by default, needs to be reported to them as its premium and premium related posts are not permitted here, per WordPress guidelines.
Good luck.
