This occurs with a collada export with default skeleton and helper geometry...
Having removed all the clothes helpers, I'm going through the various vertex groups, and selecting the lowerleg02_L vertex group, I get a stray vertex selected on the right leg:
toe2-3_L also appears to have some problems
If I come across more, I can post a list.
And two questions: is there a reason why the ankle helpers aren't selected with foot_L or foot_R, and why the left and right selections are so different?
I'm using nightly r1959