Wayne,
I went through exactly the same issues with my little 350 MAC mid-drive. I put up with the intermittent problem for many hundreds of road miles. It finally failed on the stationary trainer so I could test the halls as you did. One was not shutting off, just as yours is. As crossbreak suggested, I finally bought a sensorless controller. It works fine as basically a pedelec, which is OK for the long distance road riding I do. If I was doing a lot of start/stop riding in town, or off-road riding, it would not do, as it acts just like a failed hall much of the time, if you try to start the motor without pedaling. I have a thousand miles on the sensorless controller now, and will never have to worry about halls again. I just wish someone would devise an external position sensor for these motors.
I went through exactly the same issues with my little 350 MAC mid-drive. I put up with the intermittent problem for many hundreds of road miles. It finally failed on the stationary trainer so I could test the halls as you did. One was not shutting off, just as yours is. As crossbreak suggested, I finally bought a sensorless controller. It works fine as basically a pedelec, which is OK for the long distance road riding I do. If I was doing a lot of start/stop riding in town, or off-road riding, it would not do, as it acts just like a failed hall much of the time, if you try to start the motor without pedaling. I have a thousand miles on the sensorless controller now, and will never have to worry about halls again. I just wish someone would devise an external position sensor for these motors.