There is an inconsistency in the naming of the field 'Documentation'. It is called 'Documentation' in the Editor, but is called 'Description' in the Explorer, the Collaboration Hub and when generating a Process characteristics report.
This is a known issue and has already been forwarded to our developers to get this fixed. If you are affected by this issue and want to be kept up to date about this issue, please create a ticket in our Support Portal and reference the ticket number SPM-14449.
KBA , BPI-SIG-PM-DOC , Process Documentation for SAP Signavio Process Manager , Known Error