"Wrong" of her? At 66 years old, performing a physically challenging role 8 times a week, plus all of the press events that they've been doing, the woman must be exhausted.
Plus, who are you to judge when you don't know the whole story? There are a plethora of reasons why she may need a month off. And if the producers gave her permission to take that month off, it must have been a compelling reason.
"The Spectacle has, indeed, an emotional attraction of its own, but, of all the parts, it is the least artistic, and connected least with the art of poetry. For the power of Tragedy, we may be sure, is felt even apart from representation and actors. Besides, the production of spectacular effects depends more on the art of the stage machinist than on that of the poet."
--Aristotle