Yup. It's called compartmentalizing. My therapist told me that he has to keep his personal life separate from his professional life; client A separate from client B, etc. I think many professionals do the same. I can't be thinking about my personal issues and focus on my students in class. I can't allow my personal feelings about any particular student interfere with my professional interactions with that student, grades, etc. No matter how much I like them (not sexually - that's just NO!), I can't grade them differently; I can't even really let on to them that I might like them more - it's just not professional. Therapists even more so are under those kinds of restrictions, and their ability to professionally compartmentalize allows them to be effective and to not burn out.
So, no they aren't exactly "themselves" when we interact with them. They are their professional selves. That may be a very different person from their private self.