Main page showing old/deleted post

I keep running into a problem, where the site I manage for work shows a much older post when I access the site. If I’m logged in, it will show the most recent posts, but if I’m not, or using a different browser, it shows a posts from a year ago, that no longer exists. The other strange part is when I access the site from my phone, I get the most recent posts. I’ve cleared the cache, and disabled all plugins to see if one of them was causing a conflict, but neither helped. Does anyone have any ideas?
The website is: WYBF.com