HR Employee is Holding a Grudge

Are there any suggestions for addressing the following situation, Or should I just remain professional and polite and not address the situation directly at all?

One of the two HR generalists is visibly holding a grudge against me. He/She is curt and sometimes ignores me when I directly say hello in the mornings or in passing. He/She will often be pointed and unproffesional until he/she sees another person in the conversation in which case she changes her demeanor noticably.

I don't know what situation inparticular his/her is holding against me, but I know that I can often be assertive and stick to my standard in terms of hiring standards.(High D)

This would not concern me greatly were it not for my worry that his/her inability to let go of a grudge will effective my ability to hire great employees. HR is the gate keepers for my interviews I don't get to see the resumes for phone screenings.