Moisture can make powder clump and interfere with measuring or release. Its storage and the dispenser condition are relevant when product remains after a cycle.
Understanding this situation
A compacted lump is not the same as an accurately measured fresh dose. Adding more powder can increase residue without addressing the original dispensing problem.
A useful next step
Follow the detergent maker's storage guidance and the appliance's filling instructions. Use the correct quantity rather than guessing from a damp scoop. If the problem continues with suitable product and loading, report the programme and where the residue is found.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.