So this just happened to me and I'm quite confused by it. As it turns out, the .NET Constructor Node not only provides terminals for error in, error out and the reference, but actually two more "hidden" terminals:
Notice: I left the error terminals untouched and none of the wires are connected (try it yourself). This never occurred to me. Only now, while hunting a null reference exception I found the constructor node looked "off", like this:
The strange part is that the terminal doesn't actually carry the reference (which is why I receive the null exception). It only specifies the type. The upper left terminal is a void type input, so the wire is always broken.
Does anyone know why these extra terminals exist? They don't seem to be part of the specification as far as I can tell.
Any fancy things we can do with this?