I have created a private, broadcast Chatter group. I have a Visual Flow, triggered by a Process Builder process on a record change that will post a message to the Chatter group.
Based on user reports users are getting errors in the Visual Flow:
Error Occurred: You don't have permission to do this.
So I gave the user executing the Flow access to the group with the Manager role, and the problem cleared up.
Here's where it gets strange. There's a user, let's just call her "Sally" sharing the same role and profile as the user I had to grant Manager access to in the Chatter group who is not only able to execute the Flow and post into the group, but she has full access to all group settings. She is not an admin, nor is she the group owner or even a member of the group. Her manager (her superior role) is group owner, however.
Why is Sally able to change all group settings and post in the group when others sharing the same profile and role cannot?