Is it just 1 image that always skips?
If so then please move that image into a new folder with only that image in it. The run the batch with only that image so you can watch it. Does it run the image and find the face? Or does it hunt around looking for the face and never find it.
Also, does the file name have any of these characters in it. The plugins API can’t save images with any of these characters in the name.