This appears to be the same issue as Workflow Permissions Block Getting Message - I have a user that can read a bundle and the components within it, but when those components are under workflow (started by someone else) when they open the component there's a error notification:
Unable to retrieve item with id "tcm:263-374068-131104"
Unable to open requested item
You do not have permission to perform this action.
If I add the Workflow Management right to this user's group, the error goes away, but the user now has the Administration tab and access to the Workflow Management area which is undesirable.
The resolution in the other article was hotfix CME_2013.1.1.88509 - is this still an issue in SDL Web 8.5 requiring a hotfix?
The error also goes away once the workflow activity is assigned to my users group. Previously the activity was assigned to a different user - so I guess the error makes sense in one way, user A reading a component user B has under workflow - but it seems like a bug as user A has rights to read the component, it should just show as locked out to the other user's workflow, not error?