Making the assumption that the Material Room screenshot is the "before" one.

It looks like the problem is that the Specular_Color is being set to white when the file get reloaded.
Try disconnecting the map from "Specular_Color" (keep it set at black) and set "Specular_Value" to 0.0, save, reload, and see if it makes a difference.

(Getting highlights on transparent areas is a classic P4/PP PITA)

Have you tried using "Ignore Shader Trees" and using the "Simple" Material Room view to set things up for the P4 renderer.