Given the number of recurring TOS characters and the likelihood of harassment of each, I think we could make an educated guess as to which.
Also considering it's in Grace Lee Whitney's own autobiography, and she's discussed the depths of her dilemmas on "Entertainment Tonight." She'll be the first to tell you that the daily struggle of a single mother trying to look good for 60s TV, while raising two children and devouring diet pills (among other substances), that her contract was not renewed after the first thirteen episodes.
Contractually, TOS couldn't afford Grace Lee. IIRC, her early contract was "play or pay", ie. she was paid for thirteen episodes even though the writers only fitted the character into six scripts in those thirteen weeks. By contrast, Nichelle Nichols and Majel Barrett were treated like "day players"; they only got paid for the days they worked - at least in the first year for Nichelle.
With the budget of TOS so tight, and falling behind all the time, they were
looking for reasons to let Grace Lee go. She was costing the production money. What made her so upset was that she really loved the two Rand-heavy scripts she
didn't get to perform: "Dagger of the Mind" and "Galileo Seven".
I have no doubt that someone sexually harassed her as well; in the 60s the ol' casting couch was how many actresses were expected to get steady work. But she's the first to admit (at a convention here in Oz in the 80s) that sometimes she look so hagged in the morning that the makeup artists had to work hard to get her ready for the stage lights.
