The user needs to identify cooking areas and controls accurately. Fading may be cosmetic, but it can affect safe positioning and selection.
What the observation means
Strong chemicals and abrasion are relevant history. A guessed circle or handwritten label may not match the actual heating or detection area.
A useful next step
Stop using uncertain controls and obtain model-specific advice about the surface. Use the manufacturer's documentation to describe the issue, not to justify an improvised permanent marking. Report any heat or sensing change separately; faded printing alone does not establish which internal component is faulty.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.