So frustrating. That actually pattern usually points to a safety feature kicking in or a failing part. Start with the simple stuff and plug it straight into a wall outlet, not a power strip. Hit the reset on any GFCI outlet. Let it cool fully, then turn it on and see if the timer still feels about ten minutes. If it shuts off faster when you are at the highest setting, drop the heat a notch and test again. Clean the plates & the seam near the hinge when the tool is cold. Built up residue can trap heat and make the thermostat trip early. Do a gentle cord swivel test while it is on. If the light flickers or it powers down with cord movement, the wire at the hinge is failing. If none of that changes the behavior,, the internal thermal switch or sensor is likely drifting out of spec. That is not fixable at home. If it is still under warranty, reach out. If you replace it, look for wider plates to cover more hair at once, strong heat recovery, and an auto sleep that is at least half an hour. Makes long thick hair sessions much less stressful.
