J2 Calibration

J2 has a weird issue which may be encoder related - I go through the calibration sequence and when ARCS says it's back up at -90 degrees it's only at about -45.

I will switch one of the encoders with one from a different joint to see if the issue is the encoder itself or something else.

Has this been observed before, and if so is there something else it could be that I'm missing?

Thanks in advance for any help. I'll post the results of the encoder body switch here once I do it in the coming days.