I have an entity Project and a many-to-many self-referential association (Project_Version). In a microflow I'm retrieving a list of the projects' versions but this list is always empty. I must add that in a separate microflow I am setting the association of the versions to the project.
A many to many self association is never easy to handle. Could it be, that your retrieve is retrieving the wrong side of the association? Meaning it does not retrieve objects referenced by your object but objects referencing yours.