Flexible materials can have different chemical limits from toilet ceramic or pipe surfaces. Damage may affect sealing.
What the observation means
A discoloured connector, loose joint and active leak are different observations. Cleaning cannot repair a split or incorrect fit.
A useful next step
Use only permitted external care and avoid pulling or twisting connections. If a leak or damaged material is visible, stop connected use and request assessment. Do not apply adhesive, clamp harder or wrap the connector with tape while the system remains in service.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.