SMUSH KEEPS ASKING ME TO RESMUSH SAME IMAGES

With the Smush plugin I do a bulk Smush and it says all the images are Smushed. But then if I come back to the Smush page on a later day or click Recheck images it always says I have images that need to be Smushed again. I do that but after a recheck it says they need to be smushed again:

"you have 26 images that need re-compressing!"

No errors in the debug log! FTP credentials already sent