Sounds like you're missing the binding field in the corresponding curve template of the profile you're using. Have a look at the profile the roast is using to make sure all curve templates have their binding set.
For a number of reasons, the copy function for roasts gives precedence to a profile-based workflow - it does not actually look at the data curves of the source roast. So, when you copy a roast, the copy grabs the profile from the source roast, and populates its Data Curves from the templates it finds there. One of those is probably missing its binding - or, it has outdated binding information.