A short programme has less time to wet, move, wash and rinse the load. Its capacity can therefore be lower than the large kilogram figure printed on the front of the machine.
Understanding this situation
The headline capacity usually belongs to a specified programme under stated conditions. Packing that amount into a quick cycle can leave detergent poorly distributed or soil insufficiently removed even when the appliance is operating normally. Bulky items add another issue: they need room to move, so volume matters alongside dry weight.
A useful next step
Look up the quick programme's own load limit and intended soil level. Use it for the type of lightly soiled laundry described by the manufacturer, rather than treating it as a shorter replacement for every wash. For a poor-result enquiry, explain both the chosen cycle and what was in the drum so the limitation is visible.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.