unable to assign knowledge workflow tasks to other users

Summary:

We created a user for authoring purposes with minimal roles (Resource, Knowledge Author, and Employee).

Additionally, we created a custom role to provide access to manage tasks as suggested in the following document. Added below privileges
CSO_MANAGE_TASKS_PRIV 

CSO_KNOWLEDGE_USER_MANAGEMENT_PRIV 

Currently, We are able to create knowledge articles, start the workflow and review tasks. However, we are unable to assign tasks to other users. Not able search users

User has resource and did resource setup properly.

We are facing same issue with Knowledge manager role user also. Admin user is able to assign these tasks.