The component operates in a demanding electrical and heat environment. Household adhesive is not a suitable repair or insulation method.
What the observation means
A visible crack does not establish that it is the only cause of poor ignition. The burner and controls still require correct assessment.
A useful next step
Leave the affected function unused and provide the full hob model. Do not bend the electrode, close a gap by force or test it by touching nearby metal while ignition runs. Appropriate replacement and fitting should use confirmed compatible parts and competence.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.