Snap cursor - wrong positioning with three vertices Again, I have a quite strange problem: my cursor snaps to the wrong position when used with three vertices.

For testing purposes, I made an equilateral triangle:



As on the third figure, when all three vertices are selected, and I use Snap > Cursor to Selected, the cursors snaps out of center. In all other cases, snapping is correct. It snaps to the middle of two vertices, and to the center of four vertices, and Blender correctly transforms the origin to the center of mass, if told to.

Even more strange: If I reload factory settings, the snapping works as intended. So there must be some mysterious setting saved with the blend file. There are no double vertices or zero faces. I'm at a complete lost here. Please advise.
It's stated pretty clearly in the Blender manual, but if someone omits this source it'll be here:


  The Cursor to Selected option is also affected by the current Pivot Point. For example:
  
  
  With the Bounding Box Center pivot point active, the Cursor to Selected option will snap the 3D cursor to the center of the bounding
  box surrounding the objects’ origins.
  When the Median Point pivot point is selected, Cursor to Selected will snap the 3D cursor to the median of the object origins.