Not always, but sometimes when you assign a node, that is within a internal node network, to a shader outside of this network (like in your normal shader group), all the shaders leading up to the assigned shader, and it itself, will be uncaptured from internal networks shader groups. Little bizarre. Easily fixed by "Capture Nodes" from the group in question, just thought it was odd. Keep getting startled by a lot of white borders when returning to internal node networks time to time xD