Tool fails only in model 10.0

I am trying to create a model to create schema change files for 3 replicas.

I can create the changes xml using the interface and the Compare Replica Schema tool. Once I add the tool to the model it fails with generic error 000582 for 1 of the replicas. The other 2 replicas compare successfully in the model.

I have tried creating a blank model, dragging the completed tool from the Results window, and running. It fails with the generic error.

Any clues why the tool would only fail in the model and only for 1 of the replicas?