Background - I am a manager in a hierarchically structured engineering department, broken down by engineering discipline (process, electrical, environmental, etc). In larger projects we work more like a matrix organization, but for small projects led within a disciple, we work in a more traditional format. I have 3 direct reports within 1 of the discipline. My manager is the discipline manager and he has 4 reports in addition to me, all senior level individual contributors. My manager reports to the director of engineering for the whole company. There are total of ~60 people under the director, with another ~100 with dotted line reporting. My 3 directs are less experienced engineers, ranging from 2-6 years out of college. I have been managing the group for ~2 years using the manager tools model as closely as I can.
Problem - The least experienced of my directs has twice now skipped me and my manager and scheduled meetings with the director. In both instances, she has not given myself nor my manager ANY notice that she wanted to or planned to talk to the director. In the first meeting, she asked for a promotion based on being offered a position in engineering in one of our plants. After the first instance, I talked to her about coming to me first (or at least not surprising me), how promotions work, some background on politics, and the need to consistently demonstrate results. In subsequent O3's, we discussed developmental areas and made a plan for executing the items we came up with. In the second meeting (about 3 months after the 1st, and happened last week), she reiterated her desire for recognition and reminded him about her contributions. The director reiterated the same talking points as above. She is a high D with achiever pattern. She performs well. We have weekly O3's and a good relationship. (As a side note, we have been working on a raise for her since before the 1st instance, but it has taken forever due to challenges with our HR department. In the normal course of business, she would be up for promotion this summer/early fall).
Since my first explanation of how the world works clearly did not work - any advice on what to do next?
Thanks in advance!