This really is a shock. This is the fact that, again, HR should be involved and employees should be trained on how to discuss performance, whether it be positive or negative.
I always say it’s like a cookie. You have a positive, then you talk the negative, but you end with a positive. This coworker, supervisor, whoever she was, did not have the training that they should have had in order to give this employee feedback on the project that they were working on. Bottom line.
Training, training, training. Let people know that it’s not all negative. You need to be positive.