I'm pretty sure Wordpress is hacked.

Whatever is doing it has some server side smarts. When you first load the page it does its spammy redirection to the wagon site (which ends up closing the page for some reason). Reload it and it just stays on the correct site.

Switch to a different IP address (I have a few to chose from) and the wagon site loads again. Reload and you are back to the right site.

Something in the Wordpress install is doing something malicious and doing its best to hide the fact that it does it the first time people visit the site.