Additional CSS disappears

Hi!

Last week and twice the additional CSS of the site disappeared. Just like that.

First time I requested a backpup restore. The second time I just pasted a backup of the CSS because it seems the CSS is the only problem and to avoid to be reposting articles some of which send to FB.

However I’m still worried why is this… I don’t know when/if it happens again.

Has anybody heard of this?

Thanks!

The page I need help with: [log in to see the link]