Professional and personal development never cease to be realities. This is true for everyone.
Most of the time it takes longer and feels different to learn something than it does to use acquired knowledge. We know this, but when we run into it unexpectedly it can cause some frustration or flare ups of impatience.
People can be self aware about their development or not. In the best of cases, this means that people can either know for themselves or find out that their work colleagues are on the same page and can see what is going on for the person.
What is tougher is when there is an employee evaluation and either management doesn’t really understand the employee’s development or perhaps worse, is when the management knows what is going on but the employee is not self aware about it. That can be hard to deal with without causing a lot of crying etc. or simple rage at not being granted a raise or promotion and having unpleasant problems pointed out to them.
Most of us find it difficult even when most kindly put, to be told about our shortcomings, especially if we fear getting fired over it.