str_L ... I broke something I'm not sure what I pressed but I botched something. I was rigging my first character with Blenrig 5 by the tutorial on the Blender Cloud and this happened. I tried to fix it by loading the factory settings, uninstalling and reinstalling Blenrig 5 from the master zip file. I loaded Blender's Vincent from the public file and it still does this when I grab the red cube controllers, so I'm pretty sure I hit a check box in my interface and it's something in my configuration (blenrig 5 reproportion layer 32). I can't find it so I'm using Patrick as my profile picture for now.
with the Blenrig 5 armature selected, in the properties pane with the data tab selected(bottom right in factory settings), there is actually a "reproportion mode" button. If this button is not selected, the problem I had above will occur.