The compact and the default view in the Collaboration Hub and the Preview doesn't show the visualization.
Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental.
This is a known bug and our development is working on a solution to fix the issue.
KBA , BPI-SIG-HUB , SAP Signavio Process Collaboration Hub , How To
SAP Process Collaboration Hub by Signavio all versions