slight strokes, major strokes, dementia, etc can influence behavior...it has been said that they take down the barriers , so you get people with no filters. that could very well be what you are experiencing with her. if she had a tia (small stroke) or the onset of dementia or Alzheimer's, parkinsons , etc...these could easily effect her behavior towards people. you may not have even noticed any other issue (physical) regarding her behavior or even the stroke itself if it was small.
I saw it in my mother after her first tia and then with each additional stroke and then her dementia. with each incident, her filter became less of a filter. they don't realize what they are saying and it isn't worth the battle to correct it because it isn't going to happen.
my mother would also rage against vocal to e changes etc. what I finally did was just basically tone it all out. I was her primary care giver so I had no other option but to be there...at first the words hurt but once I tuned them out I did what I needed to do and that was it.