Replace fitting error

I've seen a post the other day on the Autodesk Inventor forum regarding an error that the program throws when trying to replace fittings. The error is "Replace fitting error!"

You will notice if your parts are authored fittings if the thumbnail in the assembly browser looks like a blue tee.

In the assembly the commands "Replace" and "Replace all" are throwing the error.
The solution in this case is to restart inventor with the routed systems addin disabled. Once active it picks up on these parts and they can only be replaced with replace fitting command.

And the video: