In life the hard relationships are family, this is the place we practice to forgive.
Your mum gets triggered, we all get triggered. That is "We are never upset for the reason we think we are" this will be for her, some reminder of an old hurt she still gets hurt about, you then appear as the target of her rage. Then if she is in early stage of menopause, or going through, then her hormones are ruling her.
Try not to react as this will escalate, it is very hard to hold back, not to take her upset as personal.
Mother/daughter relationships are hard. How her mother treated her, will play on you, if she grew up in dysfunctional family, she knows no different. Then you can learn from this, build up your own self worth and self love.
Give her a hug, every now and then, this bond to hug, needs no words,just support and recognition.