WP SMUSH PRO - 8 images that need re-compressing!

HI There,

I have 8 images that need re-compressing, or at list is what the plugin said.
even if I re-compress them by BULK SMUSH NOW, the plugin will notify my with the same alert after refreshing the page. How can I fix this, and why this 8 images can't be compressed?

thank you