Hop you don't mind asking, but what version of the OSF are you using? Are you running the same firmware version on both your TSDZ2s?Well I have two bikes with TSDZ2s fitted.
I upgraded both to the open source firmware without any problem and this improved the performance slightly.
The one on the elephant bike experienced a torque sensor failure. However the opensource firmware allowed me to keep using it in cadence mode. For the use this bike gets, pottering into town for shopping etc, this is probably an improved operating mode.
The other unit is working fine without problems.