Contact the engineer who carried out the work and describe when the new sound occurs. If it is accompanied by movement, leakage, a burning smell or poor operation, keep the disposer unused pending advice.
What the observation tells you
Keep the repair record and note which parts or connections were attended to. A sound after a changed baffle may need a different check from one after mounting work, but neither should be diagnosed remotely from timing alone. Do not retighten or reposition recently serviced parts.
A useful next step
Provide a short recording only if it can be obtained without operating an unsafe appliance. Agree the next assessment before continuing regular use.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.