After consumer complaints of overheating batteries, the company did not immediately report the defect with its Ionic smartwatches, according to a settlement with the U.S. government.

Fitbit failed to report overheating incidents involving its Ionic watches in which customers suffered serious burns, safety regulator said.

Fitbit received numerous reports of the Ionic smartwatches overheating while being worn by consumers, causing some consumers to sustain burns including second-degree and third-degree burns on their arms or wrists.

The civil penalty follows 115 reports of overheating, including injuries ranging from second to third-degree burns.

Your workout warm-up instructions didn't say anything about setting wrists on fire – allegedly! Years after recalling one of its smartwatches over overheating batteries that burned people, Fitbit has agreed to pay a $12.