Bean add form submit handler not called when another module alters the form

When used in conjunction with another module that alters the form's submit/validation handlers, bean's own own handlers no longer get called. This other module is doing it in the correct way:

  // Validation and submit function.
  $form['#validate'][] = 'manualcrop_validate_crop_selection';
  $form['#submit'][] = 'manualcrop_save_crop_selection';