Are many-to-many relationships also supported in ArcGIS Online?
I am trying to add a new many-to-many relationship to a feature class that already has a one-to-many relationship. When I added the relationship and published it, the second relationship was not in ArcGIS Online and the original relationship's ID had changed from 0 to 1, breaking the Esri Leaflet function I have to find related records. https://developers.arcgis.com/esri-leaflet/api-reference/tasks/query-related/
I had to delete the many-to-many relationship to get my application to work properly again.
As an aside, the Create Relationship Class geoprocessing tool in ArcGIS Pro is really unreliable, I think because it is so slow. Dropdown values revert to previous values and incorrect error messages appear while setting parameters. It takes several minutes and several attempts to set the parameters.