Never seen this before on a leader. For some reason, the leader will not attach where I place it on the part. It jumps out to the edge and adds an extension line. see the video here. http://screencast.com/t/JAeJFW17s
As a workaround I can move the leader off one of the edges and let it put the solid dot at the end of the leader.
Any ideas on how to not get it to add the extension line to the end of the leader?
I think i had this problem once too... though i can't remember how i solved it.
It either had something todo with the model itself (iam or ipt) and i did a rebuild on all involved files...
Or it might have been that the view on the idw wasn't entirely isometric and i had to reorient the view.
I'm not sure if this will help, but you could try and see if it might.