Diagnosis
Product buildup (hairspray, oils) on the glossy black sensor strip is interfering with its ability to accurately read hair temperature and adjust power.
How to Fix It
Power off, unplug, and let the styler cool completely. Use a cotton swab dipped in a tiny amount of rubbing alcohol. Gently wipe the glossy black 'Ultrazone' sensor strip that runs between the plates. Wipe dry with a clean side of the swab. Do not scrub; be gentle.
If That Didn't Work
If the strip appears scratched or cloudy, cleaning won't help. Physical damage to this optical sensor is permanent. The styler will still work, but the 'predictive' temperature regulation that adjusts for hair thickness won't function optimally.
Heads Up
Never use anything abrasive, like a scrub pad or toothpaste, on the sensor. Do not submerge the styler. Avoid getting the alcohol on the matte black plastic housing, as it can cause discoloration.