Why does Symantec's Autodetect feature in BackupExec only work about half the time?

So, I have an Exchange 2010 server with a Symantec BackupExec 2010 server backing it up, and I keep getting failed jobs with the following error:

Backup of Exchange 2007 fails with 'Error: 0xe00002f7 - Cannot extract mailbox messages from the Exchange backup'

And the solution from Symantec is the following:
http://www.symantec.com/business/support/index?page=content&id=TECH125276

V-79-57344-759: Final error: 0xe00002f7 - Cannot extract mailbox messages from the Exchange backup.

Solution

1. Go to Backup Job properties of the Exchange job

2. Select Microsoft Exchange under Settings

3. Change the "High Availability Server (Exchange 2007 or later)" drop down to "Back up from the active copy only (job fails if not available)"

Note : This solution only applies to Microsoft Exchange 2007 which is NOT in a clustered environment.

Why is it that Symantec BackupExec's automatically detect "feature" for just about anything in backup exec only work about half the time?  The other half of the time, they tell you "oh, just turn it off and you'll be fine"...