I find that when calibrating the power meter via the Edge 1040, it doesn't display the number like it normally did like in the Edge 1030 Plus. The display only states "Torque" and nothing else. Also after an hour or so of riding, the power meter started returning low power numbers less than 100w even pedaling hard on flats. It may have to do with a sudden temperature change of more than 5 degrees Farenheit.
I started calibrating the power meter via the stages App and with a temp change of at least 5 degrees F, and I didn't see the same issue.