It will affect your financial standing for other things: like "Do you own a property (not your primary residence)?" and "Provide details of your part of any loans?". Even if you aren't paying anything, you technically own half that house. Which means when asked you need to declare it.

Doesn't matter if don't derive anything from it, you are legally able to due to being on the mortgage.

I think you need to call and speak with a more senior person at CL, because technically, you own two houses, and only one can be deemed a primary residence.