The DataLoader crawls the Journal mailbox in Exchange but does not clear out all of the messages, they appear to be 'stuck' and a corresponding error "Unable to obtain property 850B001F; unexpected property type 000B." is seen the DataLoader wlog in the ArchiveManager\DL directory.
The mapping table in the EDB may be having issues.
This would normally occur after creating a new EDB or moving the Journal to a new database or after performing Exchange maintenance.
To resolve this issue; create a new EDB file and create a new Journal mailbox in the new EDB and restart the Data Loader service.
