The rim is exposed to room air whenever the lid opens, and any obstruction to closure can add moisture. The exact pattern helps distinguish ordinary accumulation from a persistent gap.
What the observation tells you
Check for packaging or a basket handle crossing the sealing line. Do not press down on the lid with extra weight or scrape the seal with a metal tool. A distorted lid needs assessment rather than stronger closing force.
A useful next step
Follow the model's maintenance guidance and record where frost returns after correct care. Include whether the lid closes evenly and whether recent loading changed its movement.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.