pallin position defining the end of a wall

[bagiolino]

It's been a long time since I wonder why the ball that indicates the ends of a wall (those that serve to stretch or shorten the wall), when intersecting other walls do not coincide with the actual length of the object but they penetrate the adjacent walls!
I attach the image because it is not easy to understand what I mean.
If I drag a ball until I touch the inner surface wall of the adjacent wall, as soon as I click with the mouse returns where it was.
thanks in advance.

 

[gfrank]

the joint affects 3 walls.
verify the type of joint and the associations of the 3 walls

 

[bagiolino]

the image placed refers to the intersection between 3 walls (among other things different from each other), but I happen the same thing also at the intersection at 90° between 2 walls of the same type.
Is it normal and it happens to you, or when I design the walls, do I have to be careful to enable or disable any function? ?
Thank you gfrank!