Bug? - Sprites in Sprite Sheets commit suicide when adjusting the grid/anchor point

Hey,

In my project, when I slice up a Sprite Sheet, drag the frames into the Hierachy view to create a Animation and then try to adjust the Grid or Anchor Points in the Sprite Editor, the name of the frame in the Project view as well as the Frame in the Animation goes missing.
When I create a new Animation containing one of those nameless parts of the Sprite Sheet, Unity doesnt recognise it in the Animation view if I select it in the Animator/Project view.

Added a few pictures, maybe somebody can reproduce this:
(I'm using the newest patch release, 4.6.2p2 I think, but I had the same Issue with 4.6.1p1)



Animation not recognised after I created it by dragging Sprites that "lost" their names into the project view:



Also, I get several Errors:



And this Error: argumentexception invalid path system.io.getdirectoryname
which i was unable to reproduce.

I know its all a bit vague, but maybe somebody can reproduce the Issue.

And last but not least one of the Sprite Sheets I get the Error with:


Thanks,
Claas M.