It shows a sound or pressure interaction at another fixture. The symptom may involve the route as well as the pump itself.
What the observation means
A gurgle does not prove a particular blockage or valve defect. Keep its timing relative to ordinary flushing or pumping clear.
A useful next step
Describe the connected fixtures and stop use if levels rise or drainage slows. Do not pour extra water into each waste to trace the sound. Venting or pipe alterations require appropriate assessment rather than owner experiments with caps or valves.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.