This is still an issue in BP.
If a material (e.g., DefaultTextMaterial) is assigned to an object material element and then, with “Construction Script” a dynamic material instance of the same material (DefaultTextMaterial) is created and assigned to the mesh again, the editor crashes.
But I have found a solution: First use the default material, e.g., DefaultTextMaterial or BasicShapeMaterial in my case, then create a dynamic material instance of not the same material, e.g., MI_MPR-COR in my case and assign it to the mesh (see figure).
