Missing Voltage

Hello all,

I seem to be having a problem with the electric currents model. I have a boundary current source defined for an object in a poorly conductive medium. Over the domain of the object the current ranges from negative to positive, and what I'm seeing is that after solving, (in some circumstances) the voltage everywhere will either be positive or negative (IE. the scale bar showing potential will stop at 0)

Any help with the issue will be greatly appreciated.

Thanks,
Aaron R. Shifman