Only use a monitoring arrangement compatible with the appliance and instrument instructions. A cable crossing the sealing surface can prevent full contact and create the very warming problem being investigated.
What the observation tells you
The gap may be small but can admit moist air and produce local frost. Crushing the lead can also damage the sensor. A thin cable is not automatically harmless, and cutting a notch in the gasket is not an acceptable solution.
A useful next step
Use a suitable approved placement or wireless instrument where appropriate. Check closure after positioning and remove an unsuitable arrangement safely. Report any resulting seal damage.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.