3D Printing Forum

I've made this cookie cutters with rhinoceros 6 and  checked the stl file with Meshmixer and they seem fine. However, when slicing it on Cura 4.8 it creates inner squares as a wall which are not inteded to be there at all. Does anyone know if it is  a problem of the modelling, the mesh or the way I'm setting Cura? Does it happen oftenly when modelling with Rhinoceros for 3D printing?
To the post i attach the stl file and the pictures of what I 'm reffering to 

Thank you very much for your help

Hi 3dmuza welcome to the forum
I have looked at your model and it looks OK. I have imported it into Cura 4.8 and it looks OK.
On the view of the small area, where is that as I cant see it in Cura?

Lez