The Q50 was made with 2 trunk configurations. One configuration does not have a spare tire compartment, while the other one does.
If you have a spare tire in your trunk (check under the cargo flooring, if you are not sure), then you have the optional compartment.
This compartment effects which cargo liner you need, because they are different floor pans.
When choosing your cargo liner, please be sure to choose the correct configuration - the fitment notes will direct you to the correct cargo liner.