By definition, yes, but by intention or spirit is often in question. Game designers are fallible, system mastery design is often imbalanced with intent to allow exploitation. When is it working as intended or a mistake isnt as easy as definition level of correctness in my experience.
If the rules written in the book don't match the rules the designers intended to write, then they should not have released the product until it was in working order.
It also doesn't matter if there's some error or typo in the rules. As long as everyone is playing by the same rules (no matter what those rules are), and all options are equally available to everyone, it is fair.
(By way of analogy, if Akuma is a thousand times more powerful than any other character in Street Fighter, Street Fighter is still fair as long as everyone has the option of picking Akuma, or no one does.)
This seems more like a "Rules As Written vs. Rules As Intended" thing. Intentions and expectations should be addressed in Session Zero so everyone is on the same page, yeah?
The only way to discover someone's intent is to read the words they wrote.* If you think the words mean the authors intend X, then you think the words mean X. That's what meaning is. Rules as intended is rules as written, which is rules as interpreted. They all mean the same thing - whatever meaning arose in your mind as you read the words.
When people say rules as intended, what they actually mean is "This is what I think the rules mean, and I believe that I understand the rules better than everyone else."
*Someone will probably respond with something about sage advice, forum threads, twitter posts, or other clarifications external to the rulebook. This doesn't change anything I've said. In each of those cases, you discovered what the designer intended by reading what he wrote. It makes no difference if the words appear on the internet or in the book. There is no other method of discovering a person's thoughts - you must engage in communication using language in some medium. And people can have honest disagreements about the meaning of words in a twitter post just as easily as they can about the words in a book.