When you get one or more vertices that seem to stick out very farm from the figure, sometimes it's caused by the falloff zone not being big enough to enclose all the vertices, but that shouldn't show up at zero pose.  It may be that you have a bit of geometry that's in the wrong group - if you have a little "island" of verts that are, say, members of the chest group, but are completely surrounded by members of the hip group, then it could show up this way.  Auto Group frequently creates problems just like this.  I encourage you to group the model manually, in your modeling app.

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