"Project Unavailable" error when selecting or moving to a referenced feature model


I have noticed a bug regarding switching between feature models. It only occurs if the VS project you are working in is not the first project you have opened since you started Visual Studio.
Clicking on the button with 3 dots when editing the "Definition Feature Model Diagram" results in the error "Project Unavailable".
The "Project Unavailable" error also occurs if you already have a feature model reference set up, and you click on the arrow in the bottom-left corner of a node in order to move to the referenced feature model.
Both errors only seems to occur if your current project is not the first project you have opened in Visual Studio during your working session. If you restart Visual Studio, and then the first project you open is your feature model, the errors do not occur.