Trim can alter an opening or resonate with airflow. The timing helps distinguish an installation change from an unrelated internal fault.
What the observation means
Do not remove fixed guards or obstruct a vent to see whether the noise stops. A decorative strip fitted near a slot can have functional consequences.
A useful next step
Describe where the trim was added and the programmes involved. Keep the specified ventilation clear. If overheating, scraping or an electrical smell accompanies the sound, stop using the cooker and seek assessment rather than assuming the new noise is only cosmetic.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.