[ODE] Problem with amotors and ball joints

[Brad]

I'm trying to apply stops to a ball joint using angular motors. When I 
create a ball joint and an angular motor, with stops on every axis of 
the angular motor except one, with the hi and lo stops all set to 0, the 
ball joint behaves like a hinge, which is correct. But if I set one of 
the hi or lo stops to 0.0001 or -0.0001 (respectively), which should 
have a negligible effect, the joint behaves completely different.

Is this a bug or am I doing something wrong? I've got the amotor set up 
in user mode with all the axes anchored to the global frame.