According to Dataviz's Exchange Attachments Synchronization Errors and Solutions, the error code 0x7370007 means:
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There is an email that is causing the error.
Please see the conflict resolution steps for a conflict with an Email item.
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Conflict resolution is here:
DocID: 14030 - Is my sync failing because of corrupt Outlook data?
And the referring page is here:
DocID: 14363 - Documents To Go with Exchange Attachments Synchronization Errors and Solutions
I voted for the bug as well, but I'm curious if anyone finds this error to be specific to a particular email / attachment, or if it's happening across the board.