She had just recovered from COVID. We don’t know how that affected her health or concentration.
I saw her stellar performance on Saturday afternoon. She occasionally - and gracefully - glanced at the script but never hesitated or fumbled a line. She’s a pro, and if carrying those pages helped her and her fellow cast members, it’s fine with me. It seems ungenerous to criticize her for it. (And I remember the early days of Encores productions, too.)