When using the WorkspaceConnectionString Property (CIMStandardDataConnection) to update the source of a feature class within a feature dataset, it updates the source but breaks the source connection (red exclamation point).

Additional Information

Workaround

Since the CIM data source definition of the existing layer includes a feature dataset, but the new data source does not, it must be omitted from the CIM. One way to do this is to create a new CIM data source object, which will not include a feature dataset:

aprx = arcpy.mp.ArcGISProject('CURRENT')

m = aprx.listMaps('Map1')[0]

lyr = m.listLayers('*States*')[0]

c = lyr.getDefinition('V3')

dc = arcpy.cim.CreateCIMObjectFromClassName('CIMStandardDataConnection', 'V3')

dc.workspaceConnectionString = r"URL=https://services2.arcgis.com/k4wsDILUIGeQ5HvW/arcgis/rest/services/USAFederalLandsFSNew/FeatureServer"

dc.workspaceFactory = "FeatureService"

dc.dataset = "0"

c.featureTable.dataConnection = dc

lyr.setDefinition(c)

Steps to Reproduce