[WP Smush Pro] Smush Pro: “already optimized”

Hi,

I’ve got a question regarding Smush Pro: Some of my media can’t be smushed/ restored. Instead of showing stats and buttons, there is only displayed “already optimized” (Sometimes button “resmush” is shown, but doesn’t work). Please see this image:

https://imgur.com/gf4Nx0b

Any idea, what to do to get this fixed?