Website Changes Left/Center Alignment in Browsers

Equinoxroof has been changing its alignment when I refresh the page in any of the major browsers. Every few minutes, the site would be left aligned, then I’d refresh, and the site would be center aligned (which is correct). Back and forth.

I emptied cache in both W3 Total Cache and browsers caches, and this problem still occurs. No one has altered the site, no one has changed any code. The site has not been edited recently, and it used to appear properly until somebody noticed a couple of days ago.

Here’s the website: http://www.equinoxroof.com
Reloading the page after a couple of minutes, the site alignment will change.

Anybody have the same issue? Any suggestions?

Thanks in advance!