DIAGNOSIS The sensor in the dehumidifier isn't always perfectly accurate, and its location matters. It's reading the air right at its intake, which might be drier if it's sitting in the path of an air vent or in a corner.
FIX First, trust your standalone hygrometer if you know it's good. You can calibrate the Cube's behavior to match. Don't worry about the number on its display—use its "Target Humidity" setting. If your room hygrometer reads 60%, set the Cube's target to 50% or 45% and see if that gets the room down to your desired level. It's about the outcome, not the displayed number. Place your standalone hygrometer a few feet away from the Cube for a better room average.
IF THAT DIDN'T WORK If the discrepancy is huge and persistent (like 30% difference), the internal sensor might be dirty or faulty. You can try gently vacuuming the intake grille on the back to clear any dust from the sensor, but there's no user-serviceable calibration for it.
HEADS UP These built-in sensors are best for relative trends, not absolute precision. As long as the unit cycles on and off and maintains a comfortable room feel, the exact number on its display isn't critical. Use it as a guide, not a scientific instrument.