First, I recommend always shooting looser than you want the final crops to be and give the software room to work. If you try to crop it in camera and also use the software to make similar crop then you will always run into this issue and it will make your job much more difficult.
For your batch, it looks like the gap mode in the batch settings is set to “fit canvas”. That setting will automatically crop tighter when you shoot to close in camera and there is empty space. It keeps the top margin and face position the same but zooms in more just enough to crop off the empty space. So it eliminates the empty space but some images are then scaled more than others out of necessity to fix the in camera crops that were too tight. When you use that option, you will be able to see which images it needed to fix the crop for in the cropData.txt file. That file will be generated by the batch and will be under the source image folder after the batch is complete.
There is also an option for content aware fill which will not zoom in but instead auto fill the area using the Photoshop content aware fill. That works well for backgrounds like old masters. However, in the case where you cut off a shoulder as in your image, the content aware fill won’t rebuild the body parts well. So only use that option if it just has to fix the background only.
The other options are to fill the area with hi-vis magenta or white. The hi-vis magenta makes it easy to see when looking at the thumbnails which images have the empty space. With the white, you may not notice when looking at the thumbnails against a white screen and then when you print those images will print with the white edge. So I wouldn’t use white.