Electric cooking surfaces and cookware retain heat. The Off setting ends the selected heating input; it does not instantly cool the surface.
What the observation means
A residual-heat indicator can help, but its exact meaning and behaviour are model specific. It should not be used as permission to touch the zone or place heat-sensitive items there.
A useful next step
Keep the area clear and allow safe cooling. If a zone appears to continue actively heating after Off, stop using the cooker and seek assessment. Do not confuse stored warmth with uncontrolled heating, but do not dismiss a clear new failure to switch off.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.