The connected waste arrangement can be relevant to a dishwasher drainage complaint. Water rising at the sink and water remaining inside the appliance are separate observations worth reporting together.
Understanding this situation
This does not identify whether the appliance or household drainage needs work. Recent plumbing changes and the behaviour of the sink during ordinary use can help establish the appropriate assessment.
A useful next step
Stop use if water backs up or leaks. Do not disconnect waste hoses or pour drain chemicals through the dishwasher. Describe the shared timing so the booking team can consider the correct scope rather than assuming a pump replacement is required.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.