I haven’t seen that happen before. I just logged into the demo to double check and it looks like everything is still working. Can you do a quick test to make sure the “Hide Content” option Saves before you exit the Customizer page? Once you click “Save and Publish” it’s supposed to save the option.
What version of the theme are you using?
Have you made any changes, updates, custom code, etc to the Theme?
Are you using any plugins that may be interfering in some way?
BTW, the link to your site is set to a Coming Soon page so I can’t see anything just yet.