Port Capacity.Multiple not working correctly, being overwritten by newest connection

[Dsearle2]

I recently added this package to our project and ran into an issue with the multiple port connection property. We have an output node with Capacity.Multiple, however when we connect this to multiple nodes, only the last connection is serialized and the rest are lost whenever the graph is reloaded (or the domain is recompiled). Is there something we are missing?

Edit: this only seems to apply to output nodes. Is it possible to use Capacity.Multiple on outputs, or would this need to be a PortList?