On some environemnt watermark effect from image_effects module does not work

Edit
src/Entity/ImageStyle.php

Add the missing getName() method.

  /**
   * {@inheritdoc}
   */
  public function getName() {
    return $this->get('name');
  }

@warwickshaw have you tried with fresh Drupla? I think this method can come from override from another class. For example imageapi_optimize also override the same class and expect it own method. It is good to know with which particular modules debugger is conflicting so we can fix that.
As an option need to think if it is possible to add magic methods for missing methods.