🇧🇷Brazil @juamerico

I had the same issue, and turned out the settings.crop_preview_image_style, on entity_form_display, was set to the same Image Style → value as the image_style on entity_view_display.
For example:

core.entity_view_display.node.machine_name.default.yml:

// some other code...
content
  image_field:
    settings:
      image_style: your_crop_size //any aspect ratio you're using.

core.entity_form_display.node.machine_name.default.yml:

// some other code...
content
  image_field:
    settings:
      crop_preview_image_style: your_crop_size //the same Image Style here.

What fixed it for me was creating a new Image Style → , with scale effect, and setting it on the entity_form_display. Like that:

core.entity_form_display.node.machine_name.default.yml:

// some other code...
content
  image_field:
    settings:
      crop_preview_image_style: scale_effect_crop_image_style //change it to the newly created Image Style.

You don't need to change anything in the entity_view_display.

I hope this helps other people (: