While charging in unusually dim lighting this morning, I noticed hairline cracks on the face of the HR sensor. Panicking, I did some research and found this has happened before to people (like me) who have not damaged the sensor in any way. I have not dropped, smashed, or otherwise done anything to the underside of the watch. It is on my wrist 99% of the time. Sent an email to Garmin support this morning and hope they can address the issue quickly. I love this thing and hate the idea of being without it.