Despite an amazing company, my supervisor seems to have been a bad apple. After more than a year of reinforcement that my contributions were respected and needed, my supervisor and an HR rep surprised me one day, and asked for my resignation just 15 days before the estimated arrival of my first child.
I did amazing things here, and strongly disputed that I ever had a performance issue. HR didn't help, and just took my supervisors word for everything. No investigations. I was given the choice of a performance-improvement-plan right in the middle of the month my partner is supposed to be giving birth, or resignation.
I later found out that the plan was in works for 2 months. From this I can only conclude that the timing was intentional. Absolutely cold-hearted and cruel.