Unexpected system generated folders after export

[akmvq]

Hi All,

I am attempting to export a users mailbox for migration. Currently, I'm using the REST API to systematically pull the mailbox onto the file system. When I open the tar.gz file, I see that there are multiple inbox folders labeled inbox!1,inbox!2, etc. each partitioned with 500 or so messages. However, there are a few system generated folder in the inbox sub folder that seem out of place. These folder have a "MessageId - MessageName" as the name of the folder and inside of the folder is simply the message and metadata with no MessageID in the names. There is also no metadata for these folders. Does anyone know how or why these folders are created? If any one could help it would be much appreciated.

Thanks.