Not all WOH listed in WOH overview

Steps to reproduce:
1. Go to docs.opencast.org
2. Open the Admin Guide for 2.2.x
3. Go to "Workflow Operation Handlers"->Overview

Actual Results:
The following WOH that appear in the navigation are not listed in the overview table:

• cover-image

• encode

Expected Results:
List should be complte

Workaround (if any):