What I am seeing here is that the setting in Grid properties>Grid line count is being interpreted as the extents in file units and not number of lines to show.
For example, I set grid line count to 10, minor grid lines every 10 units. What shows up is a grid from 0 to 10 units in +/-XY, but with only one line at 0 and another at +/-10. My interpretation is that it should be 100 units in each direction i.e. 10 minor lines *10 units per minor line. The only time it is correct is when minor grid line spacing is set to 1 unit.
I did check, Windows Rhino behavior is correct in this regard.
Before I bug report this, does anyone else see the same behavior?