Vertex Chamfer limitation

I've been using the vertex chamfer to put a 3 sided chamfer in the
inside corner of pockets. I've noticed that if the pocket is created
by extruding a sketch (whether a boss, or a cut), there seems to be a
limitation as to the size of the chamfer. It has nothing to do with
running past the edge of the part.

For example, extrude block 10" on a side, 2" thick. On the top of this
extrude a boss 6" on a side, 2" thick. Next, put an extruded cut 3" on
a side on one corner of the boss, down to the top of the 10" extrusion.
Now put a vertex chamfer in the resulting corner. The largest size
that will work is .471" and change. Why?

I haven't been able to figure out the limiting factor(s). Has anyone
else seen this problem? The only workaround that I've found is to
create sketches, planes, etc. and put an extrusion in the corner.
Since parts may have dozens of these corner, that is a real time
consuming project.

 

I'm using SW2006, SP4.1. I tried it on SP3.4. Same result.

 

Ed, It work fine on my machine (SW2006, SP3.4). what version,SP do you use?

Gil