Can favoritism turn into discrimination?

I have been working in a clinic for 22 months now. Almost 2 years. Work have been so light and easy, patients are pleasant. My only problem is the manager. I am used to being in the hospital that is more laborous work than admin stuff, but now it is the opposite.

She has been favoring all my other colleagues because when I did one administrative mistake (literally forgot to put a form in the file), she escalated it and said I needed a one month performance review. No one was harmed, no financial effects on the clinic either. And it was my first time forgetting it in almost 2 years being there.

I learned that one of my colleagues literally did the same thing, the same day she told me off. But she just had a 'verbal warning'. Then I confirmed with other 2 colleagues that they miss it from time to time too but never heard anything from the boss.

Is this discrimination? All of them grew up from where we are based, yet I'm an immigrant. I have been for 10 years so I could say that I am well-adjusted to the country, but definitely did not grow up here.

I challenged the 'performance review' and said if this is an isolated case or is this applicable to everyone who made the same mistake. Still waiting for her reply.

PS. I can't report it to HR as well because the boss is dating HR manager too. Probably next step would be union

Author: Purple_syringe