Problem management table UI actions are not working on the agent workspace List of UI actions that are not working 

1. Assess

2. Confirm

Workspace is currently for tier 1 agents so you can create a problem in workspace, but managing the life cycle of a problem is still done in the platform.
That is why the actions are not available in workspace .
The UI actions on Problem Management are used for state transitions.
This is not supported on Workspace currently as it uses UI Scripts to open up modals for filling up of mandatory fields

PRB1396417(Working as Expected)