Had a weird experience with ACR today. I did command A, or select all and it would not select all so I got them all selected with the mouse. And then after I clicked done I was left with a duplicate for each file. One had changes other did not.
If you are using ACR plugin within the Photoshop, please reset the preferences for Photoshop and check if that helps.
The reason why we have suggested to do this, if there's any changes under setting causing this issue.