Hi @jluts!
Having a look at this in more detail later on. Edit: Ok interfaces are not the problem as we are dealing with a heat transfer simulation instead of CHT. Please check your volumetric flux boundary condition. You uploaded a table stating that the volume heat flux is at 5 meters in X whereas the domain you are working with is way smaller than the dimension entered. Make sure this is correct and test it again - let me know how things go! 
Cheers,
Jousef