Can you post this example model? I'm struggling to understand what the 90 degrees in the initial measurement even means here.
Generally speaking, the angle being measured here is between the normal of the planar face and the center axis of the cylindrical face. You can see that axis being displayed temporarily while selecting the cylindrical face, and one of the vectors in the final annotation should be aligned with this axis.
And so for a planar face with a perpendicular cylinder, the angle should indeed be either zero or 180 degrees, depending on which way the normals are pointing.
If the cylindrical face is incluned relative to the planar face, then you should be seeing something like this, where the 70 degree measure is showing one vector normal to the highlighted planar face, and the other vector lying along the axis of the cylindrical face.
Does that help? Again, if you can send the part, I'd love to understand what they were seeing before.
Ok so the bug on the website is fixed so can now see attachments to messages.
The zero or 180 degree measurement result makes sense as it is measuring the angle between the normal of the plane and the axis of the conical face (extrude in same plane as planar face with 8 degree taper). To get the 8 degree measurement you will have to measure to an intenrsection curve constructed on the face, or simply Information Object commands on the face will give you half angle of a conical face.
Why earlier versions of NX were giving the 8 or 98 degree on selecting the conical face I am not sure.