Another editor-created typo
Editors are generally a very conscientious, detail-oriented type of person. But they don't always understand technical content, and this can cause them to inadvertently introduce puzzling errors. I still complain about having "modulo a large prime" changed to "module or a large prime" several years ago.
The most recent example of this was when an editor changed "adding two even numbers" to "adding to even numbers," although I don't think that I'll be complaining for the rest of my life about that one. Unlike the first example.