I've been working in ArcGIS Pro 2.0.0, and I've run into quite a strange issue with the Direction/Distance tool treating distance units as being "shorter" than they should be. I've reduced it to the following test case:
I created a new map using a projected coordinate system (NAD 1983 StatePlane Idaho West FIPS 1103 Feet) and added a polyline data set that was in the same CRS. I then used the Measure tool on a line segment and got a length of 125.09 feet.
But when I use the Create tool feature to draw a new line over that same segment, the Distance tool gives me a much larger length.
If I manually enter the "correct" distance of 125.09 feet, the resulting line is far shorter than expected.
It doesn't matter whether I just press the "D" key, right-click and select "Direction/Distance", or use the Dynamic Constraints button under the viewport; Arc acts as if a "Distance tool" foot is a lot smaller than a "map foot."
Is there something I could be doing wrong that throws the measurements off, or is Arc misbehaving?