Not the first time I hear about these negative side effects, but every time I’m reminded of the possibility I’m surprised.
It also reminds me however that my meditation practice is infinitely shallower than what people suffering negative consequences describe.
There was a time where I would practice very rigorously (for me at least) and all I can remember is that I felt more empathy and emotion but never in a bad sense. I remember getting tearful if I heard a story of human suffering, and I also remember getting quasi-orgasmic sensations with food. Never things like losing it at a traffic jam.
I wish I could recover the positives, but unfortunately I don't remember what my practice consisted of back in the day. Maybe I should go to a class or something.