Well, so did I actually. Had I not read Capt Vulcan's comment I'd never have considered that it was anyone but Chi-Chi.
Guess I wasn't the only one who thought Kaguya was Chi-Chi for a moment since she is sewing Goku's clothes. Seems that Goku and Flandre are good friends now. Remilia still sees Goku as a potential rival for Flandre's affections.
The Changed hairstyle likely threw you guys off as Kaguya's rarely shown with different hair stylse and combine that with her assuming a style Chi-chi might have used...