Yarpp is not posting featured image to Rss feed

Hi there! I have just used the dudamobile to build a mobile version of my website. The thumbnails for my post aren’t being displayed properly. Distorted and not accompanying the right post. I talked to the support at dudamobile and they said they get there links from the rss feed and that yarpp is whats blocking the correct function of the thumbnails. I went into the settings, selected use thumbnails for Rss Feed and installed the plug in rebuild thumbnails. But still no luck ?? Any thoughts? Any reason why its grabbing the wrong images and not sizing them properly?
here is the site: https://www.fumblingfitness.com (check out on mobile)

Thanks again!