One Leg missing from the signal display

One leg of my power panel went missing from the display. It used to show both power legs. I noticed it because the sense reading of power usage was ~half my FPL bill.
At first one leg showed a normal signal while the other was zero. Now the second leg has totally gone (see image below.)

My electrician checked the clamps last week and unplugged/plugged the connector. The clamps are correctly oriented and the metal contact pads on the clamps were clean and contacting.
My assumption is that the sense monitor has failed. Is this a reasonable conclusion? What is the most likely failure: clamp failure of orange box failure?

Is a factory reset likely to fix this? (Last resort as I assume I’ll lose my device detection signatures.)

Could be a defective channel I the monitor or a contact gone bad in the connector. Suggest you email support@sense.com so they can take a look.

FYI, I purchased a used sense monitor off eBay, factory reset the old one and removed it, and replaced it with the new unit keeping the original clamps. The two legs immediately started working.
So at some point the original (quite ancient) orange box partially failed.