Hi there,
I took a look at your example pages, and it doesn't look like the ad tags are quite the same. The Wordpress one is URL encoded, specifically. Can you try it with a non-URL-encoded ad tag and see if that fixes the problem? It looks like the SDK is trying to read specific values out of the ad tag, but since it's encoded it's not able to read those values. For example, if you look at the network traffic, you can see that in the VAST ad tag request, "client" is "ca-video-pub-XXXXXXX" in the non-Wordpress site but null in the Wordpress site.
Cheers,