I think Bebe wasn't feeling confortable. The lack of interacting between them, Bebe vocal base was too loud... The weirdly transition of Nicki's verses to Bebe's and the dancers..
Yeah I feel like Nicki is like mad or something there starting to give credit to Bebe and shes like "fine you can join on stage for this now", however it's refreshing to see Nicki did most of this live this time and kinda dissaponting Bebe's track was to loud you could barely hear her live singing.