Contact time is part of the approved method. Longer exposure is not automatically more effective or harmless to internal materials.
What the observation means
The relevant information is the exact product and approximate duration, not simply that the toilet was being cleaned. Adding another cleaner can create an additional hazard.
A useful next step
Follow the label's guidance and contact the manufacturer if the permitted sequence was exceeded. Keep the product details available for the service team. Do not operate repeated flushes or dismantle the unit as an improvised way to correct an uncertain chemical exposure.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.