It means you get a rave review in your 1:1 PM then, on the last day you get ranked down from E or S+ because the management "consensus" was that your accomplishments were only average to below average compared to others in your peer group. It all comes down to how willing your management is to fight over your rating and that is directly tied to their level of ambition and place in the hierarchy. If you boss is already at the top of their career ladder, they will just roll over to get the meeting over with and you get screwed. If your boss is a climber, they will try to make it sound like you discovered the cure for cancer so they can take credit for "developing" you. After that, the HR mandated "diversity" leveling occurs and you get your "holiday surprise" just before the end of year.
If they know they have to cut another 20% before October, then they pick out the ones they want to position for failure and use the "consensus" to cover their tracks.