HI Ivo, I have a small problem when publishing modules in fullwidth position. Two of my websites, both using Headlines template, have the same problem: the module is published and displayed correctly in fullwidth position, but after a few days it disappears without any reason. I have to enter the backend, select the module, press "Save" and then the module is visible for a few days.
By the way the modules are different: in one website it's only a Joomla Custom module with an image, in the other website the module is an Unite Revolution Slider. In this case I also set the cache to "None"(being a dynamic content I chose this option, thus overriding the Global Conservative Cache of Joomla) ...it looks like there is some trouble with the fullwidth position. Both the website use "Headlines" with boxed container (the same as your demo)
Thanks for your help, as usual!