SigmaStudio Probe phase units: Radians or Degrees?

Hello,

I am using the probe feature in SigmaStudio version 4.2 Build 1 Rev 1764, dated 8-23-2018.

The units on the phase axis are "radians" but look suspiciously like degrees to me. I say this because my high-frequency stimulus-to-probe phase goes from +30 radians to -180 radians when I toggle on a generic low-pass filter. I don't know of any special mathematical significance of -180 radians, but degrees would actually make sense.

Is there a labeling mistake in the Probe feature?

Thanks,