This has been happening since the 10th of January (I'm not sure if you changed something with the plugin then). But basically this is what happens. I have autoblog set up to pull featured images as well as images into the posts themselves. When I manually click 'Process', everything works as it should but when I set it up to process the feed automatically every 5 hours or daily etc. It will put images into the post but does not process the featured image! For the past couple of days I have had to delete the posts and re-process them again manually for the featured image to work.
To save time, here a screenshot of my feed