Scottrade does batch updating anywhere from 3 to 5 AM nightly. That might have been the culprit. You don't see that through the Scottrade platforms such as Elite, but you will see the message if you login to their website.
Least that's what I've hit with them a couple of times around that timeframe.
There was a database error in the overnight process which caused the symbol lists to be invisible. That error has been corrected and you should now see the lists.
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