Applying metadata presets to multiple images?

[NN635735597854188051UL]

I want to add a copyright statement to all the images in a catalog. I've created a metadata preset. I select all my images with Command-A. I then select the preset out of the User Presets section of the "Manage and apply Metadata Presets" menu. The problem is, I end up with some images having the copyright notice and some not having it. I'm stumped what I might be doing wrong.