WP Smush Pro still optimizing my images after 4 hours

Hi there,

4 hours ago I have activated WP Smush Pro and run a bulk image optimization. I have a total of 182 images out of which 179 were processed for less than one hour but some three images are still being optimized. I keep receiving "Your smush request is being processed. 3 images are remaining." for almost 4 hours and the "Smushing in progress" button is being inactive so there is no way that I can stop the process.
Could you check and see what is going on? Is this normal for 3 images to be optimized for almost 4 hours?