We often work off of team-managed project board, but we now have a team that is working on issues from multiple projects. We have created a board that is not directly tied to one project, but is pulling in issues from multiple projects. Something that is happening on this board (but none of the specific project boards) is that all issues in the same epic are stuck together in the backlog. I cannot split out one story from an epic to prioritize it separately from all the other issues in the epic (ex. 1. Issue from epic A, 2. Issue form epic B, 3. Issue from epic C) - they must all stay grouped together.
This is how the backlog looks like in this team board:

But if you navigate to the actual project backlog for these issues (the issues above are coming from 2 different projects), they appear like this:

As you can see here, there are no forced groupings. I am able to prioritize these issues anyway I want regardless of epic.
How can I stop the backlog from grouping these items together?