Check the model's lint-management advice between loads with strongly contrasting fibres. A combined machine can carry fibres from one process into the next if the specified care routine is missed.
Understanding this situation
This is especially relevant when the preceding textile sheds, but it does not explain every mark. Distinguish loose fibres from dye, detergent residue or oily material before deciding on a response.
A useful next step
Clean only the permitted accessible areas while safe and follow any documented between-load procedure. Choose compatible load sequences where practical. Report persistent contamination with the actual fabrics and order of use, rather than applying stronger products without identifying the material.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.