Yes, it's deliberate, it's a consequence of adding the "watched" icon.
Until now, "rated" was a synonym for "watched". With the new version the word "watched" has replaced the word "rated" in several places (the top icons with the numbers, the checkbox from the title search, etc...). Now "watched" means "watched", either you've rated or not.
https://www.coollector.com/help.html#watchedHopefully it's now easier to understand, especially for the new users.
When you'll export your list, it'll show the rating you've given (like before) or it'll say "watched" if you didn't rate.