The current focal review situation opens the door WIDE open for discrimination against anyone who took leave in the past year. All it takes is for a manager (who is under pressure to meet focal distributions for ssl4/5) to think "well... they did less than their peers..." They check the box for a lower stock grant, that individual is labeled a substandard employee and they are out the door.
It is not SUPPOSED to happen. The managers are supposed to account for leaves in their assessment. But this is very difficult to do and is not enforced.
Escalation for ssl4/5 decisions now goes back thru the management chain that made or bought off on the decision in the first place.
It's a mess.
If it happened to you or you even think it happened to you, file that complaint with the EEOC. It may not help in the short term but it enough complaints are filed it WILL get attention. You can keep it from happening to someone else.