Keep the disposer and its connections free from storage loads. The appliance should not act as a shelf support, step or anchor for items in the cupboard.
What the observation tells you
Additional pressure can interfere with access to controls and place strain on fittings. Conversely, wedging something underneath to support a loose appliance can conceal a mounting fault. Remove loose objects carefully only when doing so will not destabilise a suspect unit.
A useful next step
Arrange secure storage away from the appliance and keep required service access clear. If the disposer moves when the load is removed, stop and have the mounting assessed rather than replacing the improvised support.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.