Column cross section sizing

I have created a simple building model with columns/beams and have tried to set up different models to see the impacts of different cross section sizes once I have changed the span size and some other parameters. but when Ive recreated the geometry I don’t think the loads/moments are transferring down into the columns so it is suggesting a really small cross section which doesn’t seem right, i.e. a UC 152x152x23 for 8 or 10m spans. It seemed to be working in my first case, but not in the second despite having the same loads/supports etc. So I really don’t understand what is the difference between them or what I am misunderstanding.

I am sort of new to Karamba so I hope this makes sense, any help would be really greatly appreciated.