Hi @ELeriche ,
I actually went ahead and redrew a clean SketchUp Model_2.skp (398.7 KB) model (granted you will still have to draw in the rest of the windows and shading planes), the model when uploaded to the web interface reads the floors correctly. Once you download the model though, please ensure that the orientation is correct. The green axis points North as far as Sefaira is concerned.
I had our development team check the model and they are not quite sure what is happening with the model either. Was it imported into SketchUp from some other program? The axis being upside down suggests that it might have?