Since I think most of us know this stuff has been going on for decades (I've known about it for as long as I can remember), I think it's safe to say that he was very good at compartmentalizing his life.
That's not an unusual concept for some people. They can section off their job and their home life from another life entirely. It's not surprising at all.
I wouldn't be surprised if Ms Rashad knew him as a good guy when they worked together. Why not? Only a fool would be groping the women at work and drugging them. He's not going to do that stuff at work unless he's allowed himself to just get totally sloppy.
One of several personal examples I can think of with somebody compartmentalizing their life was with Jim Jones. When I was a kid and went to his church he seemed like a very nice man to me. He wasn't abusing me, like most of the adults in my young life, so he seemed perfectly nice. Then he went on to wreak havoc and kill quite a lot of people. All I knew was the nice man who didn't abuse me in any way.