This has actually been the case since I got the theme, but it wasn’t a big deal so I forgot to follow up.
If you go and have a look at http://signecane.com/blog, at the bottom you’ll see that the widgets between the comment area and the footer don’t have a white background.
The effect remains in two browsers (Chrome/Fx), with all plugins deactivated, and with functions.php file restored to a non-customised version (I have one function that includes credit on the featured blog image).
Any idea what might be causing this?
The most strange is the fact that when I’m tweaking appearance in the Customizer, the background for the widgets shows up fine.