The opening can gather smaller pieces during movement, creating a bundle with sheltered damp areas. This loading behaviour can explain an uneven finish without identifying a failed component.
Understanding this situation
Prepare the cover's closures according to its care instructions and use the dryer's bulky-item guidance. Total weight alone does not show whether the contents can separate properly.
A useful next step
Untangle only after safe normal unloading. Sort future loads sensibly and avoid overpacking. If drying remains abnormal on appropriate loose loads, report that pattern rather than relying only on a single bundled bedding cycle.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.