Google has made a large scale update to how they index securities for Google Finance.
A Google Web Search Help thread has a response from a Googler named Albert who said:
Thanks for reporting this issue! We recently made some large scale changes to the way we index our securities for Google Finance that would enable us to deal with data issues like this more easily. Yesterday, we pushed out a fix for problems similar to the one afflicting CMLP -- after testing, it seems like it has been fixed. Could you let me know if this isn't the case?
This was in response to a complaint about how Google handled a specific stock. But now, it seems Google fixed the issue because of the new way they index securities.
I am not sure exactly what they changed but Google said it was a "large scale" change to the way they "index" the securities.
Forum discussion at Google Web Search Help.