Simulink - Conflicting Signal Configuration

In Simulink, we've attempted to replace a subsystem with a model reference, by right clicking on the model and selecting Subsystem & Model Reference / Convert Subsystem to / Reference Model. When attempting to rerun the Simulation, we are producing an error message:

Conflicting signal configuration. The Simulink signal object on output port 1 of [model link] conflicts with the Simulink signal object on output port 1 of [inport of another model] since both outputs map to the same signal.

We've manually traced the signal through all the nested blocks (even using the 'highlight' features). The signal types appear to be correct.

I'm not sure how to troubleshoot this -are there ideas people can point me to?

[stozaki]

It seems that Simulink Signal Object is conflicted. Are you assigning a single Simulink Signal Object with multiple signals? Could you attach your mode?

[Tony Card]

Can't attach the model for IP reasons (sorry for being vague).

Nested within the Referenced Model, we do have two Bus Selectors that splits the signals. All signals from both bus selectors join to a single Bus Creator. The signal coming out of the bus creator is the output that eventually loops back to be the input of one of the Bus Selectors mentioned before.

The model worked appropriately until we extracted it to a referenced model. Somewhere we read that we would need to be more explicit with the input types in the referenced model (as opposed to inherit: auto). Which we have done. But are still producing the above error.