If she was spayed, she can't be in heat. Humping is usually a dominance issue. I would try and stop the behavior before it gets out of hand. Also growling need to be stopped. Don't let her get away with bad behavior, she needs to know her place in your "pack".
__________________ •·.·´¯`·.·•Julie •·.·´¯`·.·•  Chloé & Myah
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