Comment 2 for bug 1239682

It happens for me when starting from scratch:
 - new document (with my default which is in mm);
 - draw a rectangle;
 - go into Ry field and type 2;
 - drag a vertical guide to the top right corner(boundary);
 - open the guide dialog, set "Relative change" and type -2 mm in the X field;
 - the guide is where the corner should be.
Doing the steps I found also that:
 - close Inkscape;
 - relaunch Inkscape for a new document;
 - draw a rectangle: for me it's already rounded (las used style saved) but the corners are reported to be 25,110 mm while the last typed value (2,0 mm) should have been remembered;
 - measuring the rounded corner it turns out to be 7,087 mm (the value that must be typed in to get 2,0 mm).

There seems to be a factor of ~3,54 (or ~0,282) between what you type and what you get.

Attached is my default.