Diagnosis
The humidity sensor is being misled. Improper container use, covering, or food quantity outside the programmed range causes incorrect cook time.
How to Fix It
Use the sensor functions correctly. For Auto Popcorn, use only one standard 3.0-3.5 oz bag of microwave popcorn. Place it centered on the turntable. For Sensor Reheat, place food in a single layer on a microwave-safe plate. Do not cover with tight lids or metal. The total quantity must be between 4 oz and 32 oz.
If That Didn't Work
Clean the sensor area. Wipe the inside roof of the cavity with a damp cloth. There is a small sensor vent there. Grease or steam residue can block it.
Heads Up
The sensor measures steam. Very dry foods (bread, fries) or frozen foods will not trigger it correctly. Use manual time/power for those items.