I can say for sure that there is at least some truth to this theory - I was a Roma in France during WWII, and wound up in a "Research facility" in a concentration camp. I remember some of what was done to me was having my fingernails and toenails repeatedly ripped off. I was absolutely terrified of getting my nails clipped when I was little, and had to look away when anyone was doing anything to my nails. I still can't stand the thought of or execute a scratching motion with my hands, even in the air. I almost threw up when a friend of mine got her nail caught in the door at work and it came off; I can't even type it out without getting super anxious.
TL;DR, if you ever discover that you were a victim of the Holocaust in a past life, for the good of your mental health, please don't try to find those memories.
I used to cry and flip out whenever my mom clipped my finger and toenails when I was a kid. Huh. My dad had a hangnail once and that also triggered a lot of freaking out. Parents were mighty confused about that.
I am so terrified of bears that it's hard for me to feel comfortable in the woods anywhere where bears have been seen in recent times. It would make more sense for me to be nervous about wildcats, but the idea of stumbling across a bear preoccupies me for some reason. If it has anything to do with a past life I am happy enough to be ignorant of that. I like to think instead it is because most of nature that I have visited throughout my life are in areas where bears haven't been seen in centuries so I'm pretty ignorant of how to handle a bear sighting should I experience it.