Source model switches automatically on changing page in NUX

We are facing a issue where user selects a new source model on a page and then when he moves to different page the source model changes. There is 1 model for each country. The user  wants to do the planning for first country and then move to another country.

 

What really is happening is that the planner make some changes in one page and go to next page to check the result the source model changes automatically and user does not realize that he is looking at completely different data (same SKUs). 

I hope this is not by design and its a bug.