Aluminium and its finishes can respond differently from stainless steel to dishwasher detergents and conditions. A metallic appearance alone does not establish compatibility.
Understanding this situation
A darkened surface or altered finish is not the same as retained food or a fault in the dishwasher. The item's maker may specify particular care even where another aluminium product is suitable.
A useful next step
Check the exact cookware guidance and use an appropriate method. Do not increase detergent or repeat intensive cycles to remove a new finish change. Keep the item description with the selected programme when asking about an unexpected result.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.