Image Cropper Not Working Every time?

I’m trying to crop an image for the thumbnail only.

My steps:

1) upload image by clicking on add featured image.
2) click edit image.
3) select “thumbnail” for “Apply Changes to”
4) Select the area to crop.
5) Click the crop button.
6) -> The image shows in the editor as cropped.
7) click save.
8) click set feature image.

I then refresh the home page to see if the cropped image applies. I’ve gotten a variety of results:

1) It actually worked (once… and only once)
2) It doesn’t crop at all and tries to display the entire image.
3) It shows some tiny thumbnail of the entire image, in dimensions that make no sense (they aren’t coded or set anywhere).

4) on the actual post the image displays in it’s full version as intended each time.

I’m TRYING to have it to where the image fills the container. So I’ve been messing around with add_image_size and also stripping the hard coded image sizes that WP adds.

But since neither of those gave me the results I stripped all of that code out and tried cropping the image with default settings and now I still can’t even get that to display 100% of the time.

What’s going on?