Win 7 x64, 560ti 1GB
Worked: (Not sure it ever did)
If two items have a cyclic dependency with one another and you are undoing any keyframe changes on the dope sheet, the cyclic dependent items swap places with each other on the dope sheet list.
Exact steps for others to reproduce the error
Right click the keyframe on frame 0 of the Cone object, Shift+D then drag over a couple of frames and place the duplicated keyframe. Then undo the change and you will notice the two Cube objects swap places on the dope sheet. Note the cone is not constrained by/to anything, but the cubes are 'child-of' each other.
PS. I'm aware the cyclic dependency in my example is one that you would never actually use, but even the unproblematic 'acceptable' cyclic dependencies cause this issue.