No, never before, but it should work.
The cooking times for oatmeal are not listed in the cooking tables section of the instructions, see page 10 below:
https://www.wmf.com/media...
However, you can prepare oats with water, a water-milk mixture, milk or vegetable and meat stock (e.g. for soup), depending on the dish.

An AI query (GPT-5 mini) results in the following:
## Brief instructions - Fine oat flakes in the rice cooker (e.g. WMF Küchenminis)

- **Ratio oats:liquid:** 1:2 (e.g. 50 g oats : 100 ml water)
- Liquid recommendation:** Water or ¾ water + ¼ milk (milk increases the risk of burning)
- Setting:** Porridge/oat programme or normal rice mode
- Cooking time:** approx. 10-15 minutes (depending on the appliance; rice cooker usually switches automatically)
- Consistency:** Creamy - if the consistency is too thin, add less liquid; if too thick, add a little water and keep warm briefly
- Preparation:** Oats do not need to be soaked; soak for 10-15 minutes for extra creaminess (optional)
- During cooking:** If using a small rice cooker, stir occasionally to prevent burning
- After cooking:** Stir briefly, leave to stand for 1-2 minutes, refine with milk/yoghurt if necessary and sweeten/top as desired
- **Example quantity 1 portion:** 50 g fine rolled oats + 100 ml water → in the rice cooker, start the programme, stir at the end and serve.

Yes, it works for porridge, you just have to be careful and stir sometimes.