EB1b based I-485 status update (interesting !)

I-140 EB1b for university faculty position:

-ted: Feb 14,07 Approved: Feb 18, 2007

I-485:
-ted: 03/15/2007
First LUD: 03/18/2007
Finger print: 04/16/2007
Second LUD: 04/16/2007
Third LUD: 05/31/2007.

Same for spouse.

Q: What does the third LUD mean? Does it mean name check has been cleared?