I have a map document with layers that contain 1:M relationships as well as M:N relationships from a SDE. When publishing as Map & Feature Services, the M:N relationships are found in the Map Service rather than in the feature service as which is where I would expect them to be. Any ideas on why this is?
Are you working in Pro or ArcMap?
ArcGIS Pro 2.3.2
I'm wondering if this thread might be relevant to your issue: