I found an error in iron python where I get Microsoft.Scripting.ArgumentTypeException: 'Multiple targets could match' when assemblies are loaded into the ScriptRuntime.
Check InitializePythonEngine() in PythonHost to see the specific libraries that I here load manually.
It seems like the code doesn't know which assembly to call.
This didn't cause an error in versions 2.7.9 or lower of IronPython.