Header image randomly disappears in Nepalbuzz

I have a custom header image set for my home page only. The problem is sometimes it randomly disappears when I view the page. But as soon as I click on 'customize' it reappears. Any idea what might be causing this? I've tried disabling all of my plugins, thinking it might be a conflict with one of them, but that didn't seem to fix the issue either. The site URL is: http://matureservices.org/bg_matureservices.org/ (right now it appears the header image is showing correctly) Any help would be appreciated!