I don't know the answer to that. I guess since I always assumed I was the one who was mis-communicating, I have never tried to notice it.
The point I'm getting at is up until recently you assumed you were the one not communicating well, but I think you've discovered that she finds a hostile intent behind whatever you say no matter how well you express yourself. I'm wondering if she only does this with you? with only males she is related to? with all men (even talking heads on tv, etc.)? or with women, too?
IOW does she have a chip on her shoulder toward others besides you.
And I'm further hypothesizing that her career predisposes her to put a negative spin on what others have to say (and exposes her to guys--the soon-to-be-ex husbands of her clients-- who either really ARE a$$holes or whom she is hired to make look like a$$holes).
