the article says: "" Their simulations showed the vast polar structure breaking up and dispersing, indicating that the plane is not as old as originally thought and formed later in the evolution of the galaxy.""
According to Q-FFF Theory, this polar structure is based on 2e order GABHs ( Galaxy Anchor Black Holes) of smaller merger galaxies than the MW.
The breaking up is the result of the starting elliptical form of the galaxy by mutual repulsion as Herbig Haro system do. ( more 2e generation GABHs means more ellipticity.)
Also according to Q-FFF Theory is that BLACK HOLES are the same as DARK MATTER. so: The title is not correct about "at edge of " because all satellite galaxies should coexist with DM.