Hi. When some partners are mostly dedicated to a specific project, the governance needed for this project is very specific and the cost of creating a new circle (core roles, meetings, etc.) is acceptable compared to the overall cost of the project, then yes, sometimes we do.
But this is brought through a tension of the specificity (current roles don't fit the specific needs).
I would definitively not advise it as a "rule". For me, a project belongs to the operations by essence.