It can change stability or contact with the hob surface. A small missing component should not be dismissed solely because the support remains in place.
What the observation means
Rocking becomes more hazardous with a heavy or hot pan. A generic rubber pad may not tolerate the temperature or match the intended height.
A useful next step
Leave the unstable position unused and identify the compatible replacement. Do not pack the gap with foil, glue or household furniture pads. Check the complete support for damage while cool, and explain whether the problem began after cleaning or an impact.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.