>>280899999
The reason is that she isnt when Weiss was whipping her she was only employed there for like 6 months and before that she was a runaway slave who specializes in assasinations and had nowhere to go jntil Xabis thr butler offered her a job at Weiss household

She was close to her breaking point at the time when she was being whipped but she wont leave until after a while.

As for her relationship with OG Weiss in the OG timeline/Game timeline it was bad and she ran away after Weiss was expelled but in the loops it was much good but she never accompanied him to school like now